Means for changing the degree of light permeability, in particular of a greenhouse roof

摘要

A means for changing the degree of light permeability - for example of the roof of a greenhouse - has at least two sheet-like elements, connected to one another in a gastight manner along their common edges, with a compressed-gas connection in the cavity between in each case two of these elements. The surfaces of at least two of the sheet-like elements are divided into alternating regions of good and bad degrees of light permeability. By means of a superatmospheric pressure which can vary between approximately zero and a positive end value, the elements can be brought into mutual abutment and to a specific mutual spacing-apart from one another, with the result that the passage of light changes between a minimum and a maximum value.