3LCD is just another way of saying that a display uses 3 LCD panels. Most projection LCD displays use 3 LCD panels. As a matter of fact, I don’t know of any projection LCD display that does not use 3 LCD panels. But anyway, LCD technology has been moving forward, creating better displays.

Other significant developments for 3LCD projection technology this year include the introduction of HTPS panels using an inorganic alignment layer that provides users with improved contrast levels and magnificently real blacks and shadow details optimized for home theater applications. And, most recently, a 3LCD manufacturer has developed a new HTPS panel with XGA (1024 x 768) resolution using a smaller 0.6-type (1.52 cm diagonal) panel that delivers high-resolution images surpassing those achieved by preceding products.

Link: PhysOrg.com - 3LCD Manufacturers Achieve Milestones