apparatus with an optical bench and at least one optical element , which is attached on the optical bench , whereby the optical bench comprises a layer structure with an extruded honeycomb plate from light alloy , paper or char - fiber - reinforced plastic . a first cover layer is glued to the honeycomb plate and comprises a first glass - like plate , which is surface - treated on that side which faces away from the honeycomb plate . a second cover layer glued to the lower surface of the light alloy honeycomb plate and comprises a second glass - like plate . the optical bench has suspensions , which glued to one or more parts of the layer structure for force introduction into the layer structure . the optical element is fixed by cold welding or glueing on the surface - treated side of the first glass - like plate .