Resolution Capability of the Image-Orthicon Camera Tube under Nonstandard Scan Conditions

The resolution properties of the image orthicon have been studied experimentally for nonstandard scanning rates applicable in scientific observation. Resolution may be improved by (1) raising the photocathode voltage, (2) separating the exposure and scanning operations in time so as to minimize the effect of leakage of scan fields into image section, (3) cooling the target and (4) scanning slowly without reduction of bandwidth. When operated as suggested with highlights near the “knee,” the 3-in. image orthicon has an amplitude response of 50% at 900 TV-lines and a limiting resolution of about 1500 TV-lines. With increased illumination a limiting resolution of 3000 TV-lines (60 line-pairs/mm) is attained. Maximum resolution is set by capacitive coupling between elements at the target. Response to stellar or point source images is discussed. Measurement techniques and the sine-wave response of test lenses are given.

Print ISSN

0361-4573

Published

1963-10

Content type

Original Research

DOI

10.5594/J06135