Varying at least one control variable influencing at least one optical property of switchable element involves limiting temperature gradient produced by absorption of electromagnetic radiation

摘要

The method involves controlling at least one control variable so that the temperature gradient produced by the absorption of electromagnetic radiation energy at the surface of the switchable element is held below a predefined value at least at one region of the surface. The predefined temperature gradient is determined by the local breaking strength and the local permitted voltage. Preferred method: The switchable element is preferably an electrochrome or gasochrome layer. The optical property altered is preferably the reflectivity, absorptivity or light scattering ability of the switchable element. The control variable may be the degree of darkening of the element or the switching speed of the element from an initial value to a target value, the switching speed being regulated or set so that a pre-set maximum value is not exceeded. The control variable may also be a gradient of the absorption of the electrochromic radiation.