Posted by Jack Reilly on 10/10/2011 to Interesting projector lamp stuff
Radioactive Elements in Projector Lamps
Recycling projector lamps is an important responsibility of projector owners as these lamps contain toxic and radioactive material.
Most people know that many of the lamps we use contain mercury. It’s usually stamped on the box of the projector lamp. But did you know that many lamps also contain radioactive elements as well?
Krypton-85 is a radioactive element that is produced in large quantities by nuclear reactors and when processing nuclear fuels. A small amount of this gas is added to many projector lamps to help reduce the ignition voltage. Lowering the ignition voltage is important to projector lamp manufacturers as this allows them to decrease the size of the projector lamp and therefore the projector.
Alternative methods to reducing ignition voltage in arc tubes have been designed by Philips. This technique requires an arc tube to contain a small cavity or bubble before the main chamber of the arc tube. This bubble called a UV enhancing chamber contains a mercury-argon mixture and molybdenum foil that ignites at much lower voltages, which in turn allows the main chamber to ignite as well.
As more and more counterfeit projector lamp manufacturers come on the scene, we have seen a variety of methods of producing copy cat projector lamps. Some manufacturers replace the complete module, some will refit old projector lamp modules and some will replace just the burner or arc tube. Many of these tubes are greatly inferior to the original lamp manufacturer as they do not have the ability (legally or physically) to produce lamps with the UV enhancing chamber. Their answer to this problem is to utilize Krypton 85 to help lower the ignition.
Our ability to identify legitimate OEM bulbs is reduced because of the practice of some manufacturers to replace the arc tube in old Philips and Osram bulbs with an inferior arc tube. The resulting lamp is then installed in an aftermarket housing and sold as an OEM lamp as the reflector still has the familiar UHP or VIP OEM codes on the back.
How can you tell if you are getting a real OEM lamp? Good question. If you buy the original manufacturers lamp it should come in the original manufactures container with all the written material from the original manufacturer. Sometime a lamp for an Eiki projector will come in a Sanyo box. That’s OK. If the lamp comes in a plain box with no brand name, then you might get suspicious. It’s virtually impossible to tell if the lamp inside is an original or a original with a counterfeit arc tube. We suggest that you buy from reputable distributors such as AllProjectorLamps.com.
By itself a most projector lamps do not compose a threat to health or safety. When stockpiled or when not manufactured or disposed of in safe controlled ways the lamp could be a threat to people and the environment.