Cambridge, MA and Rehovot, Israel--U.S. and Israeli researchers will report on a new optical-interference-based surface for displays intended to appear different from different angles—such as glasses-free 3D displays. The solution takes advantage of mathematical functions called bidirectional reflectance-distribution functions (BRDFs) that represent how light coming from a particular direction will reflect off a surface.
The researchers will report on their results on Thursday, July 25, 2013, at 3:45 pm at SIGGRAPH 2013 (21-25 July, 2013; Anaheim, CA) in a presentation called "Fabricating BRDFs at High Spatial Resolution Using Wave Optics." The team includes researchers from Harvard University, Massachusetts Institute of Technology (MIT) Computer Science and Artificial Intelligence Lab (CSAIL), and the Weizmann Institute of Science.
By fabricating very small (200 dpi) grooves of varying depths across the screen’s surface, Todd Zickler of Harvard and his team created optical-interference effects that cause the thin surface to look different when illuminated or viewed from different angles. The paper essentially asks, “If I know what appearances I want the screen to have, how do I optimize the geometric structure to get that?” Zickler explains. Conventional photolithographic techniques are used to make the grooves.
Past attempts to control surface reflection for graphics applications have only been accomplished for surfaces displaying huge images that, for example, have pixels the size of a square inch, because their analyses did not account for interference effects. Zickler’s work, however, demonstrates that interference effects can be exploited to control reflection from a screen at micron scales using well-known photolithographic techniques.
In the future, this kind of optimization could enable multiview, lighting-sensitive displays in which a viewer rotating around a flat surface could perceive a 3D object while looking at the surface from different angles, and, even more impressively, where the virtual object would correctly respond to external lighting.
"Looking at such a display would be exactly like looking through a window," Zickler says.
