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.
Although this model was displayed it did not find commercial success until the invention of digital technology. The technology used in Plasma TV in simple language is an emissive flat panel display where light is created by phosphors excited by a plasma discharge between two flat panels of glasses.