Patent ID: 8130901

Claim:
A device for limiting an x-ray beam of a dental extraoral imaging apparatus, said device comprising a plate mechanism ( 1 ) and a drive mechanism arranged to move at least one plate element ( 2 , 3 ) of said plate mechanism ( 1 ), characterized in that the plate mechanism ( 1 ) comprises a first plate element ( 2 ) including at least a first slot ( 12 ) for limiting the x-ray beam and a second plate element ( 3 ) including at least a second slot ( 13 ) for limiting the x-ray beam, said drive mechanism including an actuator ( 4 ) arranged to directly or indirectly move said first plate element ( 2 ) independently of the location of said second plate element ( 3 ) and said second plate element ( 3 ) being arranged to be moved solely by and dependent on the movements of said first plate element ( 2 ), and that at least portions of said first and second plate elements ( 2 , 3 ) are arranged to be movable on different planes so as to enable positioning of said first and second slots ( 12 , 13 ) of the first and second plate elements ( 2 , 3 ) in an overlapping position with respect to each other so as to form an aperture for limiting the x-ray beam, the form of said aperture then being limited by both the first slot ( 12 ) and the second slot ( 13 ).