Abstract: It is an object to provide techniques for forming a field emission device of a field emission display device with the use of an inexpensive large-sized substrate according to the process that enables improving productivity. A field emission device according to the present invention includes a cathode electrode formed on an insulating surface of a substrate and a convex electron emission portion formed at a surface of the cathode electrode, and the cathode electrode and the electron emission portion include the same semiconductor film. The electron emission portion has a conical shape or a whiskers shape.

Abstract: The present invention provides a light-emitting device whose volume is small and that has plural display screens, and a personal digital assistant that realizes higher added value by using the same. A light-emitting device of the present invention has a plurality of light-emitting elements in a pixel, and these light-emitting elements emit light in a different direction from each other and a pixel driving element is provided in one of the light-emitting elements. The light-emitting device can display in both front and back sides and independently display images on the both sides. Further, it can provide a higher aperture ratio, which is obtained by adding the aperture ratios of the both sides. Furthermore, it is also possible to see different images on the both sides of an electronic device using a display device of the present invention. Moreover, weight saving and thinning of electronic devices can be realized.

Abstract: The present invention provides a step in which a channel-length of a TFT can be controlled with higher reproducibility. In addition, the present invention provides a step in which a short channel-length of the TFT can be manufactured. Further, the present invention provides a structure of the TFT in which a current-voltage characteristic can be improved. The present invention refers to a thin film transistor comprising a lamination layer wherein a first conductive film, a first insulating film and a second conductive film are sequentially laminated, a semiconductor film formed so as to be in contact with the side surface of the lamination layer, and a third conductive film covering the semiconductor film through a second insulating film.

Abstract: The present invention provides a light-emitting device that can independently display images of both front and back sides, in a light emitting device that can display in the both sides and also provides a light-emitting device in which the aperture ratio of both or either of front and back displays increases. A light-emitting device has a structure in which a first light-emitting element and a second light-emitting element that are adjacent to each other are arranged in matrix; wherein the first light-emitting element can emit light to a first side of a substrate and the second light-emitting element can emit light to a second side that is opposite to the first side of the substrate. And light-emission of the first light-emitting element to the second side is shielded and light-emission of the second light-emitting element to the first side is shielded.

Abstract: It is an object to provide techniques for forming a field emission device of a field emission display device with the use of an inexpensive large-sized substrate according to the process that enables improving productivity.