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.
Three years later, on 25th August 1934, Farnsworth gave the world its first all electronic television system demonstration with a live camera. Zworykin developed and patented Iconoscope in 1933, a new tube with better sensitivity to light. It was an improved version of Tihanyi's storage principle.