A display apparatus comprising: a backlight unit configured to emit a plurality of light waves, wherein the plurality of light waves includes a first plurality of light waves; a display panel positioned in front of the backlight unit; and an optical film positioned in front of the display panel, wherein the optical film comprises: a base layer positioned adjacent to the display panel; a first refractive layer positioned in front of the base layer and associated with a first refractive index, wherein the first refractive layer includes a pattern and the pattern includes a first inclined portion, whereby the first plurality of light waves comprises those light waves emitted after having undergone a total reflection by the first inclined portion; and a second refractive layer positioned in front of the first refractive layer, wherein the second refractive layer is associated with a second refractive index and the second refractive index is less than the first refractive index, characterized in that the pattern further includes: a pair of second inclined portions formed to define a groove; and a parallel portion parallel to the direction in which the first refractive layer extends, the parallel portion being provided between the first inclined portion and the pair of second inclined portion; and in that the second refractive layer comprises a supplement portion provided to be in contact with the pair of second inclined portions; and the supplement portion is configured to correspond to the size and shape of the groove formed by the pair of second inclined portions. a backlight unit configured to emit a plurality of light waves, wherein the plurality of light waves includes a first plurality of light waves; a display panel positioned in front of the backlight unit; and an optical film positioned in front of the display panel, wherein the optical film comprises: a base layer positioned adjacent to the display panel; a first refractive layer positioned in front of the base layer and associated with a first refractive index, wherein the first refractive layer includes a pattern and the pattern includes a first inclined portion, whereby the first plurality of light waves comprises those light waves emitted after having undergone a total reflection by the first inclined portion; and a second refractive layer positioned in front of the first refractive layer, wherein the second refractive layer is associated with a second refractive index and the second refractive index is less than the first refractive index, a base layer positioned adjacent to the display panel; a first refractive layer positioned in front of the base layer and associated with a first refractive index, wherein the first refractive layer includes a pattern and the pattern includes a first inclined portion, whereby the first plurality of light waves comprises those light waves emitted after having undergone a total reflection by the first inclined portion; and a second refractive layer positioned in front of the first refractive layer, wherein the second refractive layer is associated with a second refractive index and the second refractive index is less than the first refractive index, characterized in that the pattern further includes: a pair of second inclined portions formed to define a groove; and a parallel portion parallel to the direction in which the first refractive layer extends, the parallel portion being provided between the first inclined portion and the pair of second inclined portion; and in that the second refractive layer comprises a supplement portion provided to be in contact with the pair of second inclined portions; and the supplement portion is configured to correspond to the size and shape of the groove formed by the pair of second inclined portions. a pair of second inclined portions formed to define a groove; and a parallel portion parallel to the direction in which the first refractive layer extends, the parallel portion being provided between the first inclined portion and the pair of second inclined portion; and in that the second refractive layer comprises a supplement portion provided to be in contact with the pair of second inclined portions; and the supplement portion is configured to correspond to the size and shape of the groove formed by the pair of second inclined portions.