Circuit arrangement for detecting the amount of deposited electrode material on the wall of a lamp vessel
AssigneeU.S. Philips Corporation
InventorsGunther H. Derra, Hanns E. Fischer, Hans G. Ganser, Holger Monch
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Abstract
The invention relates to a measuring circuit for detecting the amount of deposited electrode material on the wall of a lamp vessel of a discharge lamp by measuring the power of infrared radiation within a specific wavelength range, comprising a detector for generating an electrical signal constituting a measure for the power of the infrared light in said specific wave length range. According to the invention the measuring is done in a time lapse starting after a predetermined time interval following the extinguishing of the discharge lamp. An increased accuracy of the measurement is thereby realized.
Claims18
Method for measuring the mount of deposited electrode material on the wall of a lamp vessel of a discharge lamp, comprising heating the discharge lamp to an elevated temperature and measuring the power of infrared radiation radiated by the discharge lamp within a specific wavelength range, characterized in that the measuring is done while no discharge is present in the discharge lamp.
Measuring circuit for measuring the amount of deposited electrode material on the wall of a lamp vessel of a discharge lamp by measuring the power of infrared radiation radiated by the discharge lamp within a specific wavelength range, comprising a detector for generating an electrical signal constituting a measure for the power of the infrared light in said specific wave length range, characterized in that the measuring circuit is equipped with a means for detecting the extinguishing of the discharge lamp and a means coupled with said means and for detecting with the detector for registering the power of the infrared radiation in a time lapse starting after a predetermined time interval following the extinguishing of the discharge lamp.
Measuring circuit according to claim, wherein said means for registering are coupled with means for generating an audible or visual signal in ease the measurement shows the amount of deposited electrode material to be larger than a predetermined amount.
Dependencies are inferred from the claim text.