The Overhead Projector at West Point

1949

"During the year tests were run on a new type of classroom projector, the Visualcast, which permits the instructor to project explanatory notes and sketches on a screen while being written. As a result of these tests, additional projectors have been procured and their use will be continued."  [Annual Report of the Superintendent 1949, p. 12]

I confess I don't know what a Visualcast is, but it does not sound like an opaque projector.

http://www.dean.usma.edu/math/people/rickey/dms/MO-blackboard.html

1959

In the 1959 Howitzer (p. 102) one can see the top of an overhead projector in a classroom shot in the Department of Social Sciences.

1961

In the 1961 Howitzer, on the unnumbered colored pages, there is a picture of a classroom with an overhead projector in it. There is also a free standing podium in the picture (and some of these are still around).

References:

The Annual Report of the Superintendent is on line at  http://www.library.usma.edu/archives/archives.asp .