-
elegant instrument
During the 1870s, the French optician Jules Duboscq devised this elegant instrument to project images from a horizontal surface onto a vertical screen -
vertical lantern
A similar overhead projector, on the design of Henry Morton of the Stevens Institute of Technology in Hoboken, New Jersey, sold in this period as a "vertical lantern." -
magic lamp
The concept of the overhead projector was taken from the concept of what in the 1900’s was called the “magic lamp” or the opaque projector -
how it works
The opaque projector used to a bright light to shine through a non-transparent object and with the help of mirror projected an image on the screen -
U.S. army using overheads
-
improvements
In the 1960s, technical improvements, government funds, advertising, and the experience of teachers combined to make these projectors a popular teaching aid. -
highest use
The overhead projector had not seen its highest use until the device was modernized in the 1960s -
overheads used in schools
-
U.S. military training
Overhead projectors were introduced into U.S. military training during World War II, and used at schools like the U.S. Military Academy after the war. -
color overheads were available