Electrochromic unit (1) comprises an electrochemical cell, two electrodes (3,4), an ion conductor between the electrodes, and an electrochromic material. The ion conductor is a proton-conducting membrane (2) and is a carrier for the electrodes (3,4) which are metal electrodes. The electrochromic material (7) is applied on the side of the electrode (3) away from the membrane (2). USE - Used in LCD or LED display elements. ADVANTAGE - Transparent carriers and electrodes are not required. The unit has long term stability.