Tektronix, Inc.

Norman R Franzen

Bozidar Janko

Myron A Bostwick, Jr

A post-deflection accelerating and scan expansion lens system (10) is disclosed which may be used in a cathde ray tube (12). The lens system comprises an accelerating and scan expansion lens (70) of the quadrupole type including a pair of coaxial cylindrical electrodes (72, 74) and first and second compensating lenses (66, 78) on opposite ends thereof to provide a bright image of the desired size in sharp focus and great detail on a fluorescent screen in such tube. The first compensating lens (66) is supported adjacent the input of the accelerating and scan expansion lens to provide a linear magnification of the amount of electron beam deflection produced by the vertical and horizontal deflection plates (46, 48 and 50, 52). The second compensating lens (78) includes a single electrode having an aperture (79) with opposed notches (122, 124) in the edge of the aperture on opposite sides of the electron beam axis (28) and is positioned adjacent the output of the accelerating and scan expansion lens to provide corrected geometry of the image displayed on the fluorescent screen.

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Tigard, OR, United States of America

Norman R Franzen