Primary headaches. A primary headache is caused by overactivity of or problems with pain-sensitive structures in your head. A primary headache isn't a symptom of an underlying disease. Chemical activity in your brain, the nerves or blood vessels surrounding your skull, or the muscles of your head and neck (or some combination of these factors) can play a role in primary headaches.
The first flat screen TV was invented in July 1964 by a team at the University of Illinois. ... That year, LCD screens were sold in sizes up to 42 inches.
After that for many years the majority of TV sets sold continued to have 5 inch screens. The first TV sets introduced in the US by RCA at the New York World's Fair in 1939 had screen sizes as follows: 5 inch direct view CRT, 9 inch direct view CRT, 12 inch reflected mirror image view CRT. The 5 inch screen came in both complete TV set models and a basic low end TV set without sound (you connected it to a TV compatible radio that you ...