Optical module with a measuring device

An optical element unit, comprising:

• a support section configured to engage a support device;
• a deformation section configured to engage a deformation device to deform an optical surface of the optical element unit;
• a measuring device,
• wherein:
• the measuring device comprises a measuring element configured to determine at least one member selected from the group consisting of the position of the optical element with respect to an external reference in at least one degree of freedom and the orientation of the optical element with respect to the external reference in at least one degree of freedom;
• the measuring element is arranged on a reference section of the optical element unit,
• the reference section is decoupled from the deformation section via a decoupling section so that a deformation of the optical element unit introduced by the deformation device into the deformation section substantially does not propagate into the region of the measuring element.

A method, comprising:

• deforming an optical surface of a deformation section of an optical element unit;
• and
• detecting at least one member selected from the group consisting of a position of the optical element unit with respect to an external reference in at least one degree of freedom via a measuring element and an orientation of the optical element unit with respect to the external reference in at least one degree of freedom via the measuring element;
• wherein:
• the measuring element is arranged on a reference section of the optical element unit;
• and
• the reference section is decoupled from the deformation section via at least one decoupling section so that a deformation of the optical element unit introduced into the deformation section substantially does not propagate into the region of the measuring element.