ACTIVE MATRIX SUBSTRATE

PROBLEM TO BE SOLVED: To make to possible to correct a point defect of display and further, to avoid decrease in the numerical aperture of display by superposing a picture element electrode on a signal wiring via an insulation film in a lingual piece part for connection. SOLUTION: In the lingual piece 23 for connection provided on either a picture element electrode 24 or source bus line 22 at least, the picture element electrode 24 and the source bus line 22 are superposed on each other via an insulation film. When this superposing part is irradiated with an energy beam such as a laser light beam, etc., the insulation film of this part is punched and the picture element electrode 24 is electrically connected with the corresponding source bus line 22. Since a point defect of a display is corrected by the operation, an yield of a display device can be improved. Further, since a redundancy structure area necessary for the correction is only the area for the superposing part, a bright display is attained without decrease in the numerical aperture of the display. Thus, it is possible to manufacture display devices with a good display characteristic at a good yield and low cost.