OPTICAL SHEET HAVING REFLECTIVE POLARIZER WITH CURL FREE, BACK LIGHT UNIT HAVING THE OPTICAL SHEET AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE BACK LIGHT UNIT

摘要

PURPOSE: An optical sheet, a backlight unit and a LCD device thereof are provided to reduce the inferiority of a backlight and maintain the high definition of the LCD by preventing a curl. CONSTITUTION: A reflective type polarizing plate(21) is formed into an anisotropic material with two refractive index of an extraordinary reflective index and an ordinary reflective index. A phase difference film(22) arranged in the one side of the reflective type polarizing plate changes a circularly polarized light to a linearly polarized light. A compensation film(23) is arranged on the phase difference film compensates the ordinary refractive index and the extraordinary refractive index of the reflective type polarizing plate. A diffusion film(24) uniformly diffuses light emitted from the backlight unit.