Most people call these a "Test Pattern", but this particular one is more accurately referred to as a "Test Card" since in the early days of television, it was printed on heavy card stock, and held or positioned in front of the camera.
Wikipedia (where else these days?) has a very good article on this particular RCA Test Card, along with some external links to a guy who found one of the originals in a dumpster back in 1970.
When I worked for DirecTV, we used one of these, showing how far technology has advanced sine the early days of TV.
The history of optical targets, or "test patterns" is quite interesting if you're geeky, and covers everything from the TV test patterns to the strange markings painted on aircraft and missiles to track them during flight, and conversely, strange patterns painted on the ground or roof tops to serve as resolution checks for high-flying cameras.