This disclosure provides systems, methods and apparatus for providing stacks of optical films that may be used to provide increased on-axis display brightness. In one aspect, an apparatus or system may be provided that includes a light source, a first optical film having triangular cross-section, prismatic light-turning structures, and a second optical film having trapezoidal cross-section, prismatic light-turning structures. The first optical film may be interposed between the light source and the second optical film. In further aspects, a third optical film, similar to the first optical film, may be interposed between the light source and the first optical film. In yet further aspects, one or more additional optical films, similar to the second optical film, may be positioned in the stack such that the second optical film is between the first optical film and the additional optical film(s).