Sapphire Lens: A More Popular Material

Definition of Sapphire Lens

Sapphire, whose mineralogical name is corundum, is hailed as the "never-wearing material" and is used in top luxury brands, becoming a distinguishing mark and one of the value retention factors for high-end watches. The main component of sapphire lens is aluminum trioxide that has had impurities such as iron oxide and titanium oxide removed. Chemically speaking, synthetic sapphire is no different from natural crystal. Compared to acrylic glass and mineral glass lenses, sapphire lens has a hardness of up to Mohs 9, and is resistant to reflection and scratches.

The High Complexity of Sapphire Lens Manufacturing

After obtaining raw sapphire, it needs to be roughly sliced and finely ground on large milling machines until the thickness meets requirements. The entire process involves cutting, grinding, beveling, and polishing, all of which rely on diamond tools or diamond lapping paste. The process is complex and prone to bubbles and line defects, which only become apparent after final polishing. Consequently, some sapphire Lenses are extremely expensive, costing up to $15,000 and requiring hundreds of hours of meticulous work. An anti-reflective coating is applied to the surface of the sapphire lens, a technique developed by Ukrainian physicist Alexander Smakula in 1935. This coating is formed in a vacuum by heating a mixture of Al2O3, MgF2, and HfO2 to 1800 degrees Fahrenheit to create vapor, which condenses on the sapphire lens, effectively reducing reflections and enhancing the visual experience.

Advantages of Sapphire Lens

The greatest advantage of sapphire lens is its hardness, which is second only to diamond. It is scratch-resistant and wear-resistant, making it an ideal material for high-end watch covers.

Additionally, sapphire lens has excellent light transmittance and a wide transmission wavelength range, making it a very ideal material for optical components. With regular lenses, even if you try to scratch them with a blade or a key, you might not leave any marks, but putting them in a pocket can still result in scratches because of the various dust particles encountered in daily life. When dust particles adhere to the lens and are subjected to pressure and friction, scratches may appear on the surface, resulting in blurry photos. The hardness of sapphire lens can reach 9 on the Mohs scale, and only diamond is harder, so dust in the environment cannot scratch it.

Moreover, sapphire lens has extremely high optical transmission rates and low scattering, which can present more vivid colors. When used in camera equipment, it can make the photos appear clearer and brighter.