UHP lamp within housing which is filled with a heat conducting solid
Publication Date: 2005-Nov-22
The IP.com Prior Art Database
UHP lamps can explode. This results in glass debris (glass from the burner and/or the reflector and/or the front glass) and a spread of the gasses contained in the burner (among others mercury). Several patents describe how to minimize the negative effects of an explosion, but most ideas also have drawbacks. For example: - (DE-10150755 C1) coat the reflector with a material (high temperature resistant plastic) to prevent the debris to spread. In reality no plastics can be found that mee t the high thermal load, as these plastics deteriorate and lose their protective function; - (ID's: 695863, 695199, 696093, 697691) put the lamp in a mercury tight house, generally made from metal. For safety and thermal reasons there must be a minimum distance between the reflector and the housing. These considerations lead to quite big houses whereas most applications (especially front projection) require small units. The idea is to fill the gap between the lamp (reflector) and the housing with a material with a sufficient high heat conductivity and dielectric strength. Heat transfer by means of radiation and convection is then replaced by heat conduction.
This idea has the following advantages: - the distance between house and reflector is smaller, resulting in a smaller lamp unit; - the material between reflector and housing will keep glass debris together.
The idea is has been tested in a Concha lamp. In a Concha lamp a UHP lamp is put in a mercury...