The name Osglim is a generic term used by M-OV for a range of neon tubes. This Osglim neon tube was used by Baird as the light source for the early televisor. When connected correctly the neon glow spreads evenly across the face of the plate, that is the side opposite the horizontal wire. Reversed connections allow the glow to circle the horizontal wire.
The osglim has a filling that is 99% neon with 1% argon and the light emitted is orange-red. The lamps operate with a series resistance to limit the current to 20 - 25 mA for a maximum of 5 Watts dissipation.
The light intensity is virtually linear with current over the operating range and thus were a ready source for the early Baird Televisors. The beehive lamp was also used as a TV light source with a suitable diffuser.
The beehive Osglim when fitted with a half cylinder reflector was also believed to be used by Baird. There is a beehive Osglim signed by John Logie Baird in the Hastings museum.
Side view of the lamp.
The rear of the lamp together with the name Osglim and Made in England.
The structure of this Osglim. One electrode is the rectangular plate and the other is the horizontal bar. The plate is covered with a mica sheet that is held by tabs at the corners. This insulating layer forces the discharge to cover the other side of the plate that is not obscured by the anode wire.
Another view showing the mirror like surface of the mica sheet covering the back plate.
The wide glass tube envelope is 53 mm in diameter, and including the bayonet base is 165 mm tall.
