HBO lamps are short arc lamps in which the discharge arc fires in an atmosphere of mercury vapour under high pressure. However, a cold lamp does not contain overpressure. Since HBO lamps give off a great deal of ultraviolet radiation, they are almost exclusively employed in technical-scientific applications such as UV-curing or microlithography. So the HBO lamps are particularly applicable in the fluorescence microscopy and for the UV-curing. HBO lamps are available as reflector lamps with elliptical reflectors.