LIGHT
Light is electromagnetic radiation of varying frequencies. The human eye perceives light with wavelengths between 400 and 780nm. However, from a physical point of view, light is not limited to the visible spectrum (infrared, ultraviolet, black light, etc.). Like electric current or sound, light is characterised by its luminous flux, measured in lumens (lm), and its intensity, measured in candela (cd). Besides illuminating and making the world around us visible, light travels in a straight line in a vacuum, at a rigorously constant and extremely high speed. Thus, it has become one of the main reference points in physics and science. The second is defined by the duration of 9,192,631,770 periods of radiation of caesium 133 in transition (atomic clocks). The metre is defined by the distance light travels in a vacuum in 1/299,792,458 seconds.
Watchmaking and light are closely linked. The quality of the light in the Jura mountains favoured the establishment of Huguenot watchmakers. Light, as illumination, is indispensable to the practice of watchmaking. But it is also present in many manufacturing processes. Light is involved in all photolithographic processes (chemical etching, DRIE etching, UV-LIGA) as well as in additive technologies (electroforming, selective laser melting) and more recently in machining (laser engraving, femtosecond laser machining).
In our watches, light is present on the hands and dials, which often contain luminescent material. Today, Super-LumiNova is available in various grades of intensity.
In quality control, light is present with many measurements being performed optically (dimensions, counting, profile, etc.).