Aperture plate control mechanism for electron microscopes

Claim 2

In an electron microscope comprising a microscope chamber having a source of electrons positioned within said chamber; focusing means for directing said electrons into a beam of electrons; means for directing said beam of electrons along a path toward a specimen to be examined; a specimen stage for positioning a specimen in said beam path so that at least some of the electrons pass through the specimen; an electron-stimulated device positioned within said chamber and having a target area positioned to intercept electrons which pass through a specimen being examined; and, an improved aperture assembly disposed along said beam path and comprising: an aperture support arm extending into said chamber and being mounted for movement along the longitudinal axis of said support arm; an aperture plate having at least one passage extending therethrough in a direction generally parallel to the direction of said beam path; said aperture plate being pivotably mounted on said support arm for movement in a plane perpendicular to said beam path; first drive means for moving said support arm in a direction parallel to the longitudinal axis of said support arm to thereby vary the position of said aperture plate along a first axis; and second drive means including an elongated rod member mounted for movement in a direction parallel to the longitudinal axis of said support rod for applying a force to said aperture plate in order to rotate said aperture plate on said support arm to thereby vary the position of said aperture plate about a second axis being generally perpendicular to said first axis.

Claim 3

In an electron microscope comprising a microscope chamber having a source of electrons positioned within said chamber; focusing means for directing said electrons into a beam of electrons; means for directing said beam of electrons along a path toward a specimen to be examined; a specimen stage for positioning a specimen in said beam path so that at least some of the electrons pass through the specimen; an electron-stimulated device positioned within said chamber and having a target area positioned to intercept electrons which pass through a specimen being examined; an improved aperture assembly disposed along said beam path and comprising: an aperture support arm extending into said chamber and being mounted for movement along the longitudinal axis of said support arm; an aperture plate having at least one passage extending therethrough in a direction generally parallel to the direction of said beam path; said aperture plate Being pivotably mounted on said support arm for movement in a plane perpendicular to said beam path; first drive means for moving said support arm in a direction parallel to the longitudinal axis of said support arm to thereby vary the position of said aperture plate along a first axis; second drive means including an elongated rod member mounted for movement in a direction parallel to the longitudinal axis of said support rod for applying a force to said aperture plate in order to rotate said aperture plate on said support arm to thereby vary the position of said aperture plate about a second axis being generally perpendicular to said first axis; and, a pin member extending between said aperture plate and said support arm, said pin member extending in a direction generally parallel to the direction of said beam path; said second drive means including an elongated rod member supported by said support arm for movement in a longitudinal direction; one end of said rod member abutting at least a portion of the edge of said aperture plate so that when said rod member is moved in a direction toward said aperture plate said end of said rod member applies a force to said edge of said plate to thereby cause said plate to be rotated about an elongated axis of said pin member.

Claim 4

In an electron microscope comprising a microscope chamber having a source of electrons positioned within said chamber; focusing means for directing said electrons into a beam of electrons; means for directing said beam of electrons along a path toward a specimen to be examined; a specimen stage for positioning a specimen in said beam path so that at least some of the electrons pass through the specimen; an electron-stimulated device positioned within said chamber and having a target area positioned to intercept electrons which pass through a specimen being examined; an improved aperture assembly disposed along said beam path and comprising: an aperture support arm extending into said chamber and being mounted for movement along the longitudinal axis of said support arm; an aperture plate having at least one passage extending therethrough in a direction generally parallel to the direction of said beam path; said aperture plate Being pivotably mounted on said support arm for movement in a plane perpendicular to said beam path; first drive means for moving said support arm in a direction parallel to the longitudinal axis of said support arm to thereby vary the position of said aperture plate along a first axis; second drive means including an elongated rod member mounted for movement in a direction parallel to the longitudinal axis of said support rod for applying a force to said aperture plate in order to rotate said aperture plate on said support arm to thereby vary the position of said aperture plate about a second axis being generally perpendicular to said first axis; and, a pin member extending between said aperture plate and said support arm, said pin member extending in a direction generally parallel to the direction of said beam path; said second drive means including an elongated rod member supported by said support arm for movement in a longitudinal direction; one end of said rod member abutting at least a portion of the edge of said aperture plate so that when said rod member is moved in a direction toward said aperture plate said end of said rod member applies a force to said edge of said plate to thereby cause said plate to be rotated about an elongated axis of said pin member.

Claim 5

An apparatus as defined in claim 2 wherein said aperture plate has at least two passages extending therethrough in a direction generally parallel to said beam path.

Claim 6

An apparatus as defined in claim 2 including a cam member being mounted on a shaft for rotation about an axis generally perpendicular to the axis of said rod member and the other end of said rod member is positioned to ride on said cam member so that as said cam member is rotated about said shaft said rod member is driven in a longitudinal direction to thereby cause rotation of said aperture plate with respect to said support arm.

Claim 7

An apparatus as defined in claim 4 and wherein said shaft is coupled to an aperture control motor so that when said motor is energized said rod member is driven in a longitudinal direction thereby causing rotation of said aperture plate.

Claim 8

An apparatus as defined in claim 1 including a drive gear mounted on a shaft for rotation and at least a portion of said support arm defines a rack which engages said drive gear in a manner so that when said gear is rotated said support arm travels in a longitudinal direction.

Claim 9

An apparatus as defined in claim 6 wherein said first drive means includes indexing drive means for rotating said drive gear for a predetermined distance so that said support arm is indexed for a predetermined distance in a longitudinal direction.

Claim 10

An apparatus as defined in claim 7 wherein said first drive means includes an aperture control motor and said indexing drive means is a Geneva mechanism coupled between control motor and said drive gear.

Claim 11

An apparatus as defined in claim 2 including a drive gear mounted on a shaft for rotation and at least a portion of said support arm defines a rack which engages said drive gear in a manner so that when said gear is rotated said support arm travels in a longitudinal direction.

Claim 12

An apparatus as defined in claim 9 wherein said first drive means includes indexing drive means for rotating said drive gear for a predetermined distance so that said support arm is indexed for a predetermined distance in a longitudinal direction.

Claim 13

An apparatus as defined in claim 10 wherein said first drive means includes an aperture control motor and said indexing drive means is a Geneva mechanism coupled between the control motor and said drive gear.

Claim 14

In an electron microscope comprising a microscope chamber having a source of electrons positioned within said chamber; focusing means for directing said electrons into a beam of electrons; means for directing said beam of electrons along a path toward a specimen to be examined; a specimen stage for positioning a specimen in said beam path so that at least some of the electrons pass through the specimen; an electron-stimulated device positioned within said chamber and having a target area positioned to intercept electrons which pass through a specimen being examined; an improved aperture assembly disposed along said beam path and comprising: an aperture support arm extending into said chamber and being mounted for movement along the longitudinal axis of said support arm; an aperture plate having at least one passage extending therethrough in a direction generally parallel to the direction of said beam path; said aperture plate being pivotably mounted on said support arm for movement in a plane perpendicular to said beam path; first drive means for moving said support arm in a direction parallel to the longitudinal axis of said support arm to thereby vary the position of said aperture plate along a first axis; and, second drive means including an elongated rod member mounted for movement along an elongated axis for applying a force to an edge of said aperture plate to thereby cause said plate to rotate about a second axis being generally parallel to said beam path.

Claim 15

In an electron microscope comprising a microscope chamber having a source of electrons positioned within said chamber; focusing means for directing said electrons into a beam of electrons; means for directing said beam of electrons along a path toward a specimen to be examined; a specimen stage for positioning a specimen in said beam path so that at least some of the electrons pass through the specimen; an electron-stimulated device positioned within said chamber and having a target area positioned to intercept electrons which pass through a specimen being examined; an improved aperture assembly disposed along said beam path and comprising: an aperture support arm extending into said chamber and being mounted for movement along the longitudinal axis of said support arm; an aperture plate having at least one passage extending therethrough in a direction generally parallel to the direction of said beam path; said aperture plate being pivotably mounted on said support arm for movement in a plane perpendicular to said beam path; first drive means for moving said support arm in a direction parallel to the longitudinal axis of said support arm to thereby vary the position of said aperture plate along a first axis; and, second drive means including an elongated rod member mounted for movement along an elongated axis for applying a force to an edge of said aperture plate to thereby cause said plate to rotate about a second axis being generally parallel to said beam path.