Abstract: An optical film and a display assembly applying the optical film are provided. The optical film may comprise a plurality of truncated tapered units embedded in a material layer for transmitting a light emitted from the display unit by reflecting the light through a reflection surface between the truncated tapered units and the material layer, wherein a ratio of the area of a first end surface where the light emerges from each truncated tapered unit and the area of a second end surface where the light is incident into each truncated tapered may be between 0.2 and 0.6. Furthermore, a light absorbing layer may be formed on a light output side of the optical film for absorbing ambient light.