The plasma television panel was invented at the University of Illinois at Urbana-Champaign by Donald L. Bitzer and H. Gene Slottow in 1964 for the PLATO Computer System. The original monochrome (usually orange or green, sometimes yellow) panels enjoyed a surge of popularity in the early 1970s because the displays were rugged and needed neither memory nor circuitry to refresh the images. A long period of sales decline followed in the late 1970s as semiconductor memory made CRT displays cheaper than plasma displays. Nonetheless, plasma television relatively large screen size and thin profile made the plasma tv attractive for high-profile placement such as lobbies and stock exchanges. Screen sizes have increased since the 21 inch display in 1992. The largest plasma television display in the world was shown at the CES (Consumer Electronics Show) in Las Vegas in 2006. It measured 103" and was made by Matsushita Electrical Industries (Panasonic). Until quite recently, the superior brightness, wider color range, and wider viewing angle of color plasma televisions displays, when compared to LCD televisions, made them one of the most popular forms of display for HDTV. However since that time improvements in LCD technology have closed the gap dramatically. The lower weight, price, and power consumption of LCDs have seen them make large inroads into the former plasma market.