4K and OLED have been two of the biggest buzzwords in the realm of TVs at CES 2013, and a Sony prototype set on display at this year's show packs both those buzzwords into one 56-inch set. The prototype set offers 3840-by-2160 Ultra HD resolution on a 56-inch OLED display. It's just a prototype, but it's a very pretty one.

When the set does come to market, expect it to cost as much as a new home. Sony's existing 4K HDTV offering, the 84-inch XBR-84X900, costs $25,000 right now, and it's "only" an edge-lit LED panel; first-generation OLED sets are going for around $10,000, too.

At last year's show, Sony notably showcased a prototype Crystal LED HDTV set, which featured a different technology than OLED sets; it looks like the company will abandon that Crystal LED technology in favor of OLED sets in the future.

On the products-you-can-actually-buy 4K front, the company also announced two new 4K sets at smaller screen sizes (and prices) than the big, ultra-pricey XBR-84X900. The edge-lit 65-inch Bravia XBR-65X900A and 55-inch Bravia XBR-55X900A will be the new 4K additions, but no specific prices or availability information was announced.

Sony Electronics President and COO Phil Molyneux also teased a Sony 4K World UltraHD video-distribution service, which will allow users to download and watch 4K movies from Sony Pictures and other studios.