Patent ID: 8081321

Claim:
A scanning unit, by which a scale, which is movable in relation to said scanning unit in a measuring direction, can be optically scanned, said scanning unit comprising: a detector arrangement; a transparent support comprising a first surface and a second surface wherein said detector arrangement is arranged on said second surface; a transparent cover plate, which is fastened on said first surface of said transparent support and comprises a shielding device for shielding said detector arrangement against electromagnetic fields: wherein said transparent support with said detector arrangement is arranged in a recess of a base body, and said recess is covered by said transparent cover plate, and wherein said base body is electrically conducting, and said shielding device is connected in an electrically conducting manner with said base body; wherein said transparent cover plate comprises areas which laterally project past said transparent support, and wherein said shielding device is arranged on a surface of said transparent cover plate which faces said first surface of said transparent support; and wherein said shielding device is in electrical contact with said base body at said areas of said transparent cover plate.