Lighting Development

Press, Volume CVI, Issue 31190, 14 October 1966, Page 13

Lighting Development

'THE development of a twinA filament halogen car light has now been achieved, and is expected to revolutionise vehicle lighting. In 1960 the introduction of the iodine incandescent light heralded a new era in lighting with the combination of superior light performance throughout the life of the lamp and its exceptionally small size.

The possibilities of the iodine lamp for car headlights were soon recognised, and the Philips company developed an iodine lamp which, although much smaller than other lamps, produced considerably more light with less dazzle. There remained, however, a basic difference with the older type of car lamp containing two filaments—one for the dipped beam and one for main beam. This construction entailed great problems in the case of the iodine lamp.

In the regenerative tung-sten-iodine cycle, the tungsten is transferred from cold

to warm places. In an iodine lamp with two filaments of which only one is burning, the cold filament is chemically broken down by this cycle. For this reason the original iodine car light had one filament only, making it suitable for four headlight cars or for fog and spot lamps. However, experts have now found an answer to the problem after research into the regenerative cycle, and the new two-filament lamps may soon be available on new cars, and possibly as conversion kits for older models.