Angle relations inside a bent waveguide for a wedge display

Owing to the physical limitations of the tools used to manufacture waveguides, a some amount of bending occurs. For a wedge display, such bending would cause problems for the final picture presented as the angles of light injection into the wedge are susceptible to changes in curvature. The right-angled triangle approximation shows that a 5deg bending might be tolerable in the display, but significant distortion occurs for greater bending.