L'application cotangente des surfaces de type general

We study surfaces of general type $S$ whose cotangent sheaf is generated by its global sections. We define a map called the cotangent map of $S$ that enables us to understand the obstructions to the ampleness of the cotangent sheaf of $S$. These obstructions are curves on $S$ that we call "non-ample". We classify surfaces with an infinite number of non-ample curves and we partly classify the non-ample curves.