Each week Ross Rubin contributes Switched On, a column about consumer technology. The past decade has now seen at least three industry-wide technologies vie for the future of television -- HD, 3D and now 4K or UHD. The first of these -- HD -- represented a massive change for television that affected nearly every aspect of the TV experience from how it was captured to how it was consumed. A decade later, it is nearly impossible to purchase a TV that does not support high-definition. The second --
