Many solutions of elliptic problems on R^n of irrational slope

We consider the problem $-\Delta u+F_u(x,u)=0$ on $\R^n$, where $F$ is a smooth function periodic of period 1 in all its variables. We show that, under suitable hypotheses on $F$, this problem has a family of non self intersecting solutions $u_D$, which are at finite distance from a plane of slope $(\o,0,\dots,0)$ with $\o$ irrational. These solutions depend on a real parameter $D$; if $D\not=D^\prime$, then the closures of the integer translates of $u_D$ and of $u_{D^\prime}$ do not intersect.