Abstract: A polycrystalline silicon thin film to be used in display devices, the thin film having adjacent primary grain boundaries that are not parallel to each other, wherein an area surrounded by the primary grain boundaries is larger than 1 &mgr;m2, a fabrication method of the polycrystalline silicon thin film, and a thin film transistor fabricated using the method.

Abstract: A method of manufacturing polycrystalline silicon thin film using a laser beam to crystallize amorphous silicon thin film, the method including overlappingly irradiating the laser beam onto a region wider than 0.5 &mgr;m when crystallizing the amorphous silicon thin film.

Abstract: A thin film transistor including a lightly doped drain (LDD) region or offset region, wherein the thin film transistor is formed so that primary crystal grain boundaries of a polysilicon substrate are not positioned in the LDD or offset region.

Abstract: A thin film transistor having superior uniformity and an organic electroluminescent device using the same, and provides a thin film transistor which is characterized in that primary crystal grain boundaries of polycrystalline silicon do not meet boundaries between drain regions and active channel regions, thereby providing a thin film transistor having superior uniformity due to superior electric current characteristics so that the thin film transistor can be used in an organic electroluminescent device with superior performance.

Abstract: A headlamp and a rear combination lamp for an automobile according to the present invention comprise a clear lens without a spread optic and a prism cut, and a reflector having a single surface without any discontinuity, in which the reflector is formed as a free form reflector by using an iterative routine of an automatic designing program for the headlamps and the rear combination lamps. Accordingly, the headlamp and the rear combination lamp can indicate a desired light distribution pattern without lens prism. Further, the headlamp and the rear combination lamp can conform to the laws and regulations connected with the light pattern and accede to a consumer's demand.