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.
1 Inventors attempted to build mechanical television systems based on Paul Nipkow's rotating disks or. 2  Inventors attempted to build electronic television systems based on the cathode ray tube developed independently in 1907 by English inventor A.A. 3  Campbell-Swinton and Russian scientist Boris Rosing.