Optical film

A backlight unit comprising:

• a light emitting diode (LED) source;
• and
• an optical film having a first base film and a diffusion lens layer disposed on one surface of the first base film and including a plurality of square pyramid-shaped lenses,
• wherein each square pyramid-shaped lens of the plurality of square pyramid-shaped lenses comprises:
• an apex;
• a square-shaped base surface having four corners;
• and
• four edges joining the apex to the four corners of the square-shaped base surface,
• wherein each of the four edges of the each square pyramid-shaped lens is curved,
• wherein among the plurality of square pyramid-shaped lenses, a first and a second quadrangular pyramid-shaped lenses are adjacent to each other such that an edge of a square-shaped base surface of the first quadrangular pyramid-shaped lens contacts an edge of a square-shaped base surface of the second quadrangular pyramid-shaped lens and forms a boundary line between the first and second quadrangular pyramid-shaped lenses,
• wherein one lateral surface of the first quadrangular pyramid and one lateral surface of the second quadrangular pyramid facing each other are symmetrical with respect to the boundary line,
• wherein the light emitting diode light source is disposed under the diffusion lens layer, and
• wherein the light emitting diode light source includes a mini LED or a micro lens, and wherein the the chip size of the mini LED light source is larger than 100 μm and equal to or less than 200 μM, and the chip size of the micro LED light source is less than 100 μm.

A liquid crystal display (LCD) device comprising:

• an LCD panel;
• and
• a backlight unit disposed under the LCD panel,
• wherein the backlight unit comprises
• an optical film having a first base film and a diffusion lens layer disposed on one surface of the first base film and including a plurality of square pyramid-shaped lenses,
• wherein each square pyramid-shaped lens of the plurality of square pyramid-shaped lenses comprises:
• an apex;
• a square-shaped base surface having four corners;
• and
• four edges joining the apex to the four corners of the square-shaped base surface,
• wherein each of the four edges of the each square pyramid-shaped lens is curved,
• wherein among the plurality of square pyramid-shaped lenses, a first and a second quadrangular pyramid-shaped lenses are adjacent to each other such that an edge of a square-shaped base surface of the first quadrangular pyramid-shaped lens contacts an edge of a square-shaped base surface of the second quadrangular pyramid-shaped lens and forms a boundary line between the first and second quadrangular pyramid-shaped lenses, and
• wherein one lateral surface of the first quadrangular pyramid and one lateral surface of the second quadrangular pyramid facing each other are symmetrical with respect to the boundary line.