Abstract: Apparatus for controlling an image display device having at least one element with a reflective state in which incident light undergoes total internal reflection and a non-reflective state in which the total internal reflection is prevented. A member is positioned adjacent the element for deformation of the member between a first position in which a gap remains between the member and the element and a second position in which the member is in optical contact with the element. The apparatus incorporates a support structure having one or more display chambers. Each display chamber contains one of the elements and members aforesaid. A first aperture is provided in the support structure for air communication between the display chamber and a second chamber provided in the support structure.