Method and apparatus for observing a low magnification electron microscope image

Claim 3

In an electron microscope incorporating: A. a condenser lens system including at least one condenser lens and associated excitation current sources; B. a projector lens system including an objective lens and at least intermediate lenses and associated excitation current sources; C. an imaging means; the improvement comprising: D. a switching means arranged between the objective lens and its associated excitation current supply source for disconnecting the excitation current; E. means for replacing the final stage condenser lens aperture with an aperture having a diameter at least 0.5mm; F. means for placing a contrast aperture in the electron beam path adjacent the intermediate lens on the object side thereof; G. first means for adjusting the condenser lens excitation current so as to form a focal point on the contrast aperture when observing a low magnification image; and, H. second means for adjusting the current in the projector lens system to focus a low magnification image on the imaging means.

Claim 4

In an electron microscope incorporating: A. a condenser lens system including at least one condenser lens and associated excitation current sources; B. a projector lens system including an objective lens and at least intermediate lenses and associated excitation current sources; C. an imaging means; the improvement comprising: D. a switching means arranged between the objective lens and its associated excitation current supply source for disconnecting the excitation current; E. means for replacing the final stage condenser lens aperture with an aperture having a diameter at least 0.5mm; F. means for placing a contrast aperture in the electron beam path adjacent the intermediate lens on the object side thereof; G. first means for adjusting the condenser lens excitation current so as to form a focal point on the contrast aperture when observing a low magnification image; and, H. second means for adjusting the current in the projector lens system to focus a low magnification image on the imaging means.

Claim 5

An Electron microscope as described in claim 2 characterized in that said first means for adjusting the condenser lens excitation current is interlocked with said switching means.

Claim 6

In an electron microscope incorporating: A. a condenser lens system including at least one condenser lens and associated excitation current sources; B. a projector lens system including an objective lens and at least one intermediate lens and associated excitation current sources; C. an imaging means; the improvement comprising: D. a switching means arranged between the objective lens and its associated excitation current supply source for disconnecting the excitation current; E. means for replacing the final stage condenser lens aperture with an aperture having a diameter of at least 0.5mm; F. means for placing a contrast aperture in the electron path adjacent the intermediate lens on the object side thereof; G. first means for adjusting the condenser lens excitation current so as to form a focal point on the contrast aperture when observing a low magnification image; H. a deflecting means located below the final stage condenser lens, the excitation current source supply of said deflecting means being interlocked with said switching means so as to align the electron beam with the optical axis of the intermediate lens; and, I. second means for adjusting the current in the projector lens system to focus a low magnification image on the imaging means.

Claim 7

In an electron microscope incorporating: A. a condenser lens system including at least one condenser lens and associated excitation current sources; B. a projector lens system including an objective lens and at least one intermediate lens and associated excitation current sources; C. an imaging means; the improvement comprising: D. a switching means arranged between the objective lens and its associated excitation current supply source for disconnecting the excitation current; E. means for replacing the final stage condenser lens aperture with an aperture having a diameter of at least 0.5mm; F. means for placing a contrast aperture in the electron path adjacent the intermediate lens on the object side thereof; G. first means for adjusting the condenser lens excitation current so as to form a focal point on the contrast aperture when observing a low magnification image; H. a deflecting means located below the final stage condenser lens, the excitation current source supply of said deflecting means being interlocked with said switching means so as to align the electron beam with the optical axis of the intermediate lens; and, I. second means for adjusting the current in the projector lens system to focus a low magnification image on the imaging means.

Claim 8

In an electron microscope incorporating: A. a condenser lens system including at least one condenser lens; B. a projector lens system including an objective lens and at least one intermediate lens; C. an imaging means; the improvement comprising: D. a switching means arranged between the objective lens and its associated excitation current supply source for disconnecting the excitation current; E. means for replacing the final stage condenser lens aperture with an aperture having a diameter of at least 0.5mm; F. means for placing a contrast aperture in the electron beam path adjacent the intermediate lens on the object side thereof; G. first means for adjusting the condenser lens excitation current so as to form a focal point on the contrast aperture when observing a low magnification image; and, H. second means for adjusting the current in the projector lens system to focus a low magnification image on the imaging means, said second means being interlocked with said switching means so as to cut off the objective lens excitation current when observing a low magnification image.

Claim 9

In an electron microscope incorporating: A. a condenser lens system including at least one condenser lens; B. a projector lens system including an objective lens and at least one intermediate lens; C. an imaging means; the improvement comprising: D. a switching means arranged between the objective lens and its associated excitation current supply source for disconnecting the excitation current; E. means for replacing the final stage condenser lens aperture with an aperture having a diameter of at least 0.5mm; F. means for placing a contrast aperture in the electron beam path adjacent the intermediate lens on the object side thereof; G. first means for adjusting the condenser lens excitation current so as to form a focal point on the contrast aperture when observing a low magnification image; and, H. second means for adjusting the current in the projector lens system to focus a low magnification image on the imaging means, said second means being interlocked with said switching means so as to cut off the objective lens excitation current when observing a low magnification image.