  In this paper, we give a new formulation of invariant theory for elliptic
Weyl group using the group O(2,n). As an elliptic Weyl group quotient, we
define a suitable $\C^*$-bundle. We show that it has a conformal Frobenius
structure which we define in this paper. Then its good section could be
identified with a Frobenius manifold which we constructed in
arXiv:math/0611553.
