Patent ID: 8854743

Claim:
An optical element unit, comprising: an optical element group configured to project light along an optical axis of the optical element group; a support structure comprising an inner part partly defining a first space and a light passageway between the first space and a second space, the optical element group being disposed in the inner part; a cover device; and a holding device, wherein: the optical element group comprises first and second optical elements disposed in a region of the light passageway, the first optical element has an optically used surface; the second optical element has an optically used surface; the first optical element is connected to the support structure by the holding device; the cover device is a component separate from the holding device; the cover device is connected to the support structure; the cover device extends between the support structure and a first surface of the first optical element; the cover device is between the first and second optical elements; the cover device leaves a part of a surface of the first optical element uncovered; and the cover device covers a part of a surface of the first optical element.