Patent ID: 8810114

Claim:
An optical unit on a light emitting unit, comprising: a first polarizing plate on the light emitting unit; a second polarizing plate on the first polarizing plate, the second polarizing plate having a higher polarization degree and a lower transmittance than the first polarizing plate, an intersection angle between a polarization axis of the first polarizing plate and a polarization axis of the second polarizing plate being about 45 degrees; and a plurality of phase shift plates between the first polarizing plate and the second polarizing plate, the plurality of phase shift plates including: a first phase shift plate between the first polarizing plate and the second polarizing plate, wherein the first phase shift plate is a ½ wavelength plate; a second phase shift plate between the first polarizing plate and the first phase shift plate, wherein the second phase shift plate is a ¼ wavelength plate; and a third phase shift plate between the first polarizing plate and the second phase shift plate, wherein the third phase shift plate is a ¼ wavelength plate.