TOKYO—Convincing consumers to trade in bulky old-school televisions for slim, high-definition models was a huge success story for the TV industry. Now manufacturers are angling to kick off another buying spree.

They are gearing up to promote what the industry calls "ultra high-definition" televisions, or UHDTVs, which promise four times the resolution of existing TVs and are likely to be a hot topic at next week's Consumer Electronics Show in Las Vegas.

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