Electromagnetic actuating means for a shutter mechanism in an electron microscope

Claim 1

IN COMBINATION WITH AN ELECTRON MICROSCOPE HAVING AT LEAST ONE COIL FOR THE FOCUSING OF A BEAM OF ELECTRONS, AN ELECTRICALLY OPERATED SHUTTER MECHANISM WHICH OBSTRUCTS THE BEAM WHEN CURRENT IS FLOWING AND DOES NOT OBSTRUCT THE BEAM WHEN CURRENT IS NOT FLOWING IN THE SHUTTER MECHANISM, SAID MECHANISM COMPRISING: (A) A SHUTTER BLADE PIVOTALLY MOUNTED WITHIN SAID ELECTRON MICROSCOPE IN CLOSE PROXIMITY TO A POINT WHERE THE ELECTRON BEAM CROSS SECTION IS NARROWEST, SAID BLADE BEING CAPABLE OF MOVEMENT IN A PLANE PERPENDICULAR TO THE AXIS OF THE ELECTRON BEAM FROM A POSITION WHERE SAID BEAM IS OBSTRUCTED BY SAID BLADE TO A POSITION WHERE SAID BEAM IS NOT OBSTRUCTED BY SAID BLADE; (B) BIASING MEANS COACTING WITH SAID SHUTTER BLADE TO MAINTAIN SAID BLADE IN A POSITION WHERE SAID BEAM IS NOT OBSTRUCTED; (C) ACTUATING MEANS ABUTTING SAID SHUTER BLADE, SAID ACTUATING MEANS BEING BIASED TO MAINTAIN SAID BLADE IN A POSITION WHERE SAID BLADE DOES NOT OBSTRUCT SAID ELECTRON BEAM; AND (D) ELECTROMAGNETIC MEANS FOR MOVING SAID ACTUATING MEANS AND SHUTTER BLADE, AGAINST THEIR COMBINED BIASES FROM THE POINT WHERE SAID SHUTTER BLADE DOES NOT OBSTRUCT THE SAID BEAM TO A POINT WHERE SAID SHUTTER BLADE OBSTRUCTS SAID BEAM.