high pressure gas
Tungsten atoms (W) vaporized from a filament are deposited on an inside wall of the bulb and cause bulb blackening, so the light intensity of the vacuum lamp will decrease.
As the tungsten atoms vaporize, the filament gets thinner and finally it burns out.
Tungsten atoms (W) vaporized from a filament collide the rare gas atoms to control the vaporization.
As a result, bulb blackening decreases and it causes lower light output decrease. And due to less vaporization of tungsten atoms, the lamp life is able to be longer.
Shape of high pressure gas filled lamp
Conventionally, lamps have small exhausting tubes to vacuum and fill rare gas in inside bulb envelopes. Oshino high pressure gas filled lamps have been able to eliminate these exhausting tubes and succeeded in making compact structures and homogeneous light emitting pattern.