Patent ID: 6320331
Filing Date: 2001-11-20
Classification: A61B,H05B

Abstract:
A light source apparatus including a discharge lamp, said discharge lamp being subject to progressive degradation during use so that its output light intensity achievable with a given level of electrical input gradually decreases through its lifetime, said apparatus comprising:an output light intensity control for controlling electrical input to said discharge lamp in order to maintain output light intensity of said discharge lamp at a substantially fixed, desired intensity level;a detector for detecting an electrical parameter relating to electrical input to said discharge lamp, said electrical parameter having a tendency that its level for achieving a given level of output light intensity of said discharge lamp gradually and monotonically varies through the lifetime of said discharge lamp; andan indicator for determining when a level of said electrical parameter detected by said detector has reached a threshold level and providing an indication of necessity of discharge lamp replacement when said indicator determines so.