Nobody invented plasma and it isn't actually blood. Plasma is the liquid portion of your blood that the blood cells are suspended in. The process of separating blood for storage (plasma) was invented by Dr. Charles Drew.
Plasma screen TVs differ from LCD or LED TVs. Plasma TVs use electrically charged ionized gas to display the picture. The advantages of a plasma TV are that they provide a clearer and better picture than LCD or LED TVs.
Yes, Sony's plasma televisions are flatscreen. As a general rule, plasma televisions are made with a flatscreen design, so there are more companies than Sony if you're interested in a plasma television.