Abstract: A covering element consisting of transparent material is designed with an electro-chromatic layer for control of the transmission of light through the covering element. An electrical power which is required for control of the electro-chromatic layer is obtained from a photo-electric layer integrated in the covering element. The photo-electric layer is arranged outside the electro-chromatic layer. By means of the arrangement, when the light is at its most intensive, a high voltage is obtained from the photo-electric layer and can be transferred to the electro-chromatic layer so as to in this connection reduce, at least to a considerable extent, the transmission through the covering element. The arrangement can, within vehicle technology for example, be used in a sun-roof in order to prevent heating up of an interior space in sunny weather. By means of the arrangement, the transmission is automatically adapted according to the light.