||The Japanese lighting market is remarkably demanding on the quality of its light sources, and this 50W high colour rendering White SON lamp exhibits one of the extra features employed by Matsushita to deliver a lamp having increased stability over standard types.
The 50W White SON is primarily employed in directional spotlighting in shops and other commercial interiors, and differing burning positions can yield a change in luminous flux and colour properties of the lamp. The result is that spotlights aimed at different angles can have very slightly differing colours of light, and this is considered unacceptable to many Japanese lighting designers.
Colour stability is precisely controlled by a special transformer-ballast circuit which is required for all lamps of this type, to maintain lamp current within very tight tolerances. However it is very difficult to make a ballast which can automatically compensate for changes in burning position, and prevent variations in light colour.
This particular lamp attempts to address the problem by employing a special moulded arc tube body manufactured by NGK Insulator company of Japan, which has tapered end chambers and a larger diameter bulged central portion. This design naturally offers a far greater thermal uniformity around the arc tube than is found in plain tubular versions. The result is that when burning position of the lamp is changed, there is less overall change in arc tube temperature distribution. Consequently National's K-HICA lamps deliver better far better colour uniformity among a group of spotlights aimed at different angles.