Patent ID: 6441564
Filing Date: 2002-08-27
Classification: H05B

Abstract:
An electrical discharge lamp providing radiation and having a CRI of over 90 and a color temperature of between about 3000-4000Â° K when dimmed up to 40% of its rated power, said lamp comprising:a hermetically sealed polycrystalline alumina arc tube having an electrode at each end, said arc tube being enclosed in an outer jacket and including means for providing current to said arc tube; and a fill in said arc tube comprising a mixture of cesium, mercury and a rare gas; and means to provide a low frequency wave simmer current and means to superimpose one or more current pulses on said simmer current, the gradient of the leading edge of said pulse being short whereby to generate a high electrical field and cause a high degree of ionization of said cesium in a plasma in said arc tube whereby to enable the lamp to maintain a substantially constant CRI and color temperature when the lamp is dimmed.