2000 Osram HBO R 103W/45

This peculiar mercury short-arc lamp has several unusual features not found in other compact arc sources. The most visible one is its integrated elliptical reflector bulb provided with a multilayer interference mirror optimized for the reflection of ultraviolet radiation. Since this mirror is rejects visible light by design, it results in a very colorful aspect of the lamp, which is intended primarily for UV curing applications. The /45 suffix in the lamp reference refers to the location of its focal plane, which is 45 mm in front of the ceramic flange. That flange is used as a reference plane in light projection systems, which simplifies the source alignment in the system’s optics.

This peculiar mercury short-arc lamp has several unusual features not found in other compact arc sources. The most visible one is its integrated elliptical reflector bulb provided with a multilayer interference mirror optimized for the reflection of ultraviolet radiation. Since this mirror is rejects visible light by design, it results in a very colorful aspect of the lamp, which is intended primarily for UV curing applications. The /45 suffix in the lamp reference refers to the location of its focal plane, which is 45 mm in front of the ceramic flange. That flange is used as a reference plane in light projection systems, which simplifies the source alignment in the system’s optics.

The source of radiation is a relatively standard 100 W HBO burner with asymmetric electrodes for an operation on DC power. Its fill (mercury dose and start gas) was altered so as to increase the arc’s output in the ultraviolet. The electrode gap is only a quarter of a millimeter long, which results in an extremely high arc power density of 7 MW/cm3, one of the greatest plasma power load of all arc lamps, including xenon short-arc lamps whose power density does not exceed about 2 MW/cm3. The short arc combined with an extremely high power density thus results in an exceedingly high source brightness which enables a highly efficient optical collection efficiency of the emitted light. In order to maximize efficiency further, the cathode is positioned on the cap side of the lamp so as to limit the shadowing effect from the larger anode.