3M are perhaps best known among geeky types for their self-adhesive privacy films, that can be used to shield monitors against prying eyes, but the company has also been investigating 3D technology. They've demonstrated a 3D display system that requires no special glasses; instead, it relies on backlighting control and a specially textured adhesive film that directs elements of an on-screen image to either the viewer's left or right eye.
The 3M film has various prisms that - when paired with a display that has independent control over its left and right edge LED backlighting - direct the light to one eye or the other. The left backlight, for instance, goes to the right eye; the right backlight, thus, goes to the left eye. By changing the on-screen image between the slightly offset left/right pictures required for 3D, and flicking between the two backlighting sides, the viewer sees a combined 3D view.
Even better, when both backlighting elements are lit, straightforward 2D content can be shown with no optical interference. 3M have been demonstrating a compact 2.8-inch panel - ideal, dare we say it, for PMPs and cellphones - as well as a larger 9-inch display that uses the same system; the company claims to have begun mass production for small and medium sized displays.