A process for producing an electrochromic display device

In order to produce electrochromic display devices which contain a film of amorphous tungsten trioxide (WO3) as electrochromic layer, it is proposed, during the manufacture of this electrochromic layer, to set the relative ambient humidity to a value below 60 % and the vapour pressure of the water to a value below 14 mmHg. This production method ensures good electrooptical properties for the electrochromic layer and a high yield with relatively narrow fluctuation range for mass production.