A NUMERIC TIME INDICATION FOR DAY AND NIGHT.
Within fractions of a second, the LANGE ZEITWERK switches from one minute to the next. The grand jump occurs at the top of the hour, when all three numeral discs instantaneously advance at the same time. To make the exciting time event visible in the dark, Lange’s masters pursued an intensive research and development programme with the Fraunhofer Institute. The result is a world debut: the first watch with a luminous jumping numerals display.
THE WAY TO THE LIGHT.
In conventional watches that display the time at night, daylight is needed to “charge” the phosphorescent hands and hour markers. However, the numerals of the LANGE ZEITWERK are mostly hidden in the dark beneath the dial. To make them glow at night, it was neces-
sary to open a path that would allow sunlight to find a way into the interior of the watch. The original solid-silver dial had to be replaced with a light-permeable one. This is why sapphire crystal was chosen.
THE OPPOSITE OF SUNGLASSES.
However, a totally transparent dial that fully exposes the movement would have had negative consequences on the unique clarity of the display. Fortunately for Lange’s masters, the phosphorescent coating of the numerals is charged mainly by high-energy UV light. This made it possible to coat the sapphire crystal with a substance that allows mostly UV light, but hardly visible light, to pass through – in contrast to sunglass lenses that block UV light and allow the passage of visible light. The attentive observer will just barely be able to see the three numeral discs beneath the dial – an enigmatic design element of this watch.
