Abstract
The rapid progress made soon after the initial problems of using tungsten were solved at the beginning of this century was followed by a series of important changes at more extended intervals, but continuing to the present day when special attention to safety has given real but less apparent improvements. Besides the main stream GLS lamp development the ways in which special purpose lamps have evolved are described. Some examples of the strides in mechanisation show how great the changes have been. Halogen technology introduced in 1959 enabled significantly improved lamps to be offered in all areas where performance is at a premium, but represented difficult problems in design and manufacture for which considerable investment in research and development was necessary.
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