1984-09-19
1987-11-17
Arnold, Bruce Y.
350412, 350469, 350473, G02B 1318, G02B 934
Patent
active
047070846
ABSTRACT:
A projection lens for a cathode ray tube display which comprises from the image end a first lens unit of relatively weak optical power serving primarily to correct aperture dependent aberrations, a second lens unit of strong positive power permitting decreased equivalent focal length and resulting wide field angle, and a third lens unit having a strongly concave image side surface and serving to correct the Petzval curvature of the surfaces of the other lens units. The second lens unit comprises two elements of overall biconvex shape separated by an air gap. The facing surfaces of the two elements of the second lens unit are of relatively weak optical power and at least one of the surfaces of the two elements of the second lens unit is aspheric to contribute to the corrections provided by said second lens unit.
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Arnold Bruce Y.
Sugarman Scott J.
U.S. Precision Lens Inc.
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