General technical Informationthe construction of a lamp |
An incandescent lamp changes electrical energy to radiant energy. The visible light is generated from the filament, working as a resistor and heated up to the radiation temperature.
As filaments cannot be operated in an oxygen atmosphere, they have to be used in a vacuum sealed or gas filled glass bulb. The vacuum acts as an insulator and maintains the high filament temperature.
The basic materials used in manufacturing subminiature lamps are leadfree glass, tungsten, molybdenum and dumet wire. The soft glass is easy to handle and temperature resistant up to 370 degrees Celsius. For the sealing copper coated wires are used which consist of a nickel iron core with a copper coating. Because of the very similar temperature coefficients of glass and copper coated wire there is an excellent vacuum sealing. This is an important requirement for maintaining a high vacuum which, on the other side, assures the reliability of a lamp, long lifetime and stability in light output.
Tungsten wire is being used for the manufacturing of filaments because of its very low evaporation rate at incandescent lamp temperatures and its high melting point (3655 K).
As there are different purity grades and structures of tungsten wire, Oshino Lamps is selecting very carefully in order to use only wires of the highest quality which ensure the maximum lifetime and reliability even under shock and vibration.
The annealing of the tungsten wire is one of the most critical factors of lamp manufacturing.
The correct annealing prevents the sagging of the filament, filament deformations or premature filament breakage.
Molybdenum is used for the support - if applicable - and as a mandrel when winding the filaments.
Oshino Lamps subminiature lamps are belonging to the "T" category. The letter "T" (tubular) describes a tubular glass bulb, whereas "G" would stand for a global glass bulb. The number behind the "T" indicates the diameter in 1/8 inch steps (T1 = 1/8 inch = 3.175 mm).
Oshino Lamps is using the bead seal melting method for lamp manufacturing which is superior to other methods such as butt sealing.
The advantages of the bead seal production method are:
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