Vintage TV Magnifying Lens

Earlier tonight I watched the boxing noir The Square Jungle (Jerry Hopper, 1955). Early in the film, as we're introduced to protagonist Eddie Quade (Tony Curtis) and his ne'er-do-well father, Pat (Jim Backus), we see a small television in the scene's background. The camera doesn't call any attention whatsoever to the television, but I couldn't help but notice the large magnifying lens mounted in front of the screen, presumably as a cheap means of creating a bigger picture. That's just speculation on my part; this is the first I've ever heard of such a device. 

A quick search reveals that such devices were indeed a thing during the early television era; here's an example. Fascinating!