Backlights having stacked waveguide and optical components with different coefficients of friction

A directional backlight comprising:

• at least two light sources;
• a directional waveguide including an input end extending in a lateral direction along a side of the directional waveguide, and opposed first and second guide surfaces extending across the directional waveguide from the input end, the light sources disposed along the input end to project light into the directional waveguide, the directional waveguide configured to deflect input light to exit through the first guide surface;
• a plurality of optical components coupled to the directional waveguide to form a stack;
• and
• a support component coupled to the stack,
• wherein directional waveguide interfaces are defined between the directional waveguide and the optical components adjacent the directional waveguide, outer interfaces are defined between the optical components or between the optical components and the support component, and the coefficient of friction at the directional waveguide interfaces is greater than the coefficient of friction at an at least one outer interface on each side of the directional waveguide in the stack.