Active device having variable energy/optical properties

An active device having variable energy/light transmission properties comprising:

• an active system between a protective substrate and a protective cover , selected from an essentially inorganic electrochromic system, a light valve system, a liquid crystal system, a gasochromic system, and a thermochromic system;
• and
• a structure that is leakproof to at least one of liquid water and water vapor, which includes a surround having at least one metal based part on the periphery of the device,
• wherein the surround is attached at least partly to at least one of an edge of said substrate and an edge of said protective cover by a means for assembling that forms at least part of the leakproof structure,
• at least part of the means for assembling is conductive and includes at least one metal weld,
• the active system is arranged between two electrodes, and
• the surround is entirely metal and serves as at least a first electrical connection to one of the electrodes.