Researchers have developed a fundamentally new approach to glasses-free 3-D, called HR3D, which they say could double the battery life of devices without compromising screen brightness or resolution. Among other advantages, the technique could also expand the viewing angle of a 3-D screen, making it practical for larger devices with multiple users, and it would maintain the 3-D effect even when the screen is rotated — something that happens routinely with handheld devices.