Let
4\text≤ n\in \bfN and
W(D_n) the Weyl group of Type
D_n .Let
K be a field and group algebra
KW(D_n) is split semisimple on the field
K.for each simple module
U of
KW(D_n ), we explicitly construct a quasi-idempotent
z_U \in K\left W\left( D_n \right) \right (i.e.,
z_U^2=c_U z_U for some
c_U \in K^ \times such that
c_U^-1 z_U is a primitive idempotent and
z_UK\left W\left( D_n \right) \right \cong U as a right
KW(D_n )-module.The main results of this paper generalize the construction of primitive idempotents by Dipper and James on semi-simple group algebras of type
A and
B Weyl groups.