Here is another reference that supports the information at this link:
http://optics.perluma.com/aspheres-in-the-home
which might give a better explanation of the optical technique; see pg. 54 here:
https://worldradiohistory.com/Archive-Radio-News/40s/Radio-News-1947-09-R.pdf
V. K. Zworykin, “Reflective Optical System for Projection Television,” p. 54, Radio News, September 1947.