Focusing apparatus used in a transmission electron microscope

Patent · Tue Oct 06 04:00:00 EDT 1987

OSTI ID:6033328

Nomura, S; Kubozoe, M; Isakozawa, S

This patent describes a focusing apparatus used in a transmission electron microscope comprising: electron lens means for imaging an electron beam which has transmitted through a specimen onto an imaging plane; electron beam sensors disposed on the imaging plane; deflection means which deflects the electron beam by a predetermined angle for a short time length at least once in each of two directions in response to a change in the lens current of the electron lens means; integration means which integrates output signals of the electron beam sensors for a predetermined time length at each deflected irradiation angle of electron beam; memory means for storing separately integrated outputs produced by the integration means for each irradiation angle and for each of the electron beam sensors arithmetic means which calculates the difference between integrated values stored in the memory means and derived from each electron beam sensor at two irradiation angles and sums up differences of integrated values derived from all electron beam sensors; and lens current control means which controls the lens current of the electron lens means so that the summed output of the arithmetic means is a minimum value.

• Assignee: Hitachi, Ltd., Tokyo
• Patent Number(s): US 4698503
• OSTI ID: 6033328
• Country of Publication: United States
• Language: English

Related Subjects

440300* -- Miscellaneous Instruments-- (-1989)
47 OTHER INSTRUMENTATION
99 GENERAL AND MISCELLANEOUS
990220 -- Computers
Computerized Models
& Computer Programs-- (1987-1989)
BEAM DYNAMICS
BEAMS
COMPUTER CALCULATIONS
CONTROL SYSTEMS
DESIGN
ELECTRON BEAMS
ELECTRON MICROSCOPES
ELECTRON MICROSCOPY
FOCUSING
IMAGE PROCESSING
INCIDENCE ANGLE
LENSES
LEPTON BEAMS
MEASURING INSTRUMENTS
MEMORY DEVICES
MICROSCOPES
MICROSCOPY
MONITORS
PARTICLE BEAMS
PROCESSING
REFLECTION
SIGNALS
TRANSMISSION ELECTRON MICROSCOPY