Patent ID: 8434886

Claim:
A backlight module, comprising: an optical plate that has a light incident surface and a light emitting surface; and at least one light emitting diode (LED) disposed beside the light incident surface, and comprising: a semiconductor structure comprising a first type doped semiconductor layer, a light emitting layer, and a second type doped semiconductor layer, wherein the light emitting layer is located between the first type doped semiconductor layer and the second type doped semiconductor layer; a first electrode electrically connected to the first type doped semiconductor layer; and a second electrode electrically connected to the second type doped semiconductor layer, wherein the second electrode is an optical grating for allowing light with a first polarization direction to pass through and for reflecting light with a second polarization direction perpendicular to the first polarization direction; and a package mark formed on the LED to indicate the first polarization direction or the second polarization direction.