Tag Heuer 27 degrees of invisible hinge - a sunglasses design classic

Anyone following a little more than average my optical obsession will have noticed a slight compulsion towards hinges. Mykita has two great hinges, IC! Berlin one, Alain Mikli another (probably more), Face à Face another, Lindberg has a screwless affair and Silhouette has none at all. There are more.

Swiss watch brand Tag Heuer launched its invisible hinge in the early 2000s, with its first eyewear collection, "27 degrees". Unlike those above, its clever hinge is hidden, "invisible" even.

Some kind of mathematical magic means that by cutting the temple at 27 degrees, you cannot see inside it: open, closed or anywhere in-between.

Acclaimed British designer Ross Lovegrove was the man with the 27-degree plan - genius.

Look and learn. The video gives you an idea, but the guy from Sunglassesavantgarde.com underplays the hinge big time.