A high-pressure discharge lamp provided with an outer bulb enclosing a discharge tube accommodates a transformer having primary winding which forms part of a current conductor to one of the main electrodes of the discharge tube. The secondary winding is coupled to an ignition electrode of the discharge...http://www.google.co.uk/patents/US6034477?utm_source=gb-gplus-sharePatent US6034477 - High-pressure discharge lamp
