Patent ID: 7905613

Claim:
A backlight comprising: a light guide plate; a light diffusing optical waveguide disposed adjacent said light guide plate; a plurality of white LEDs disposed on said light diffusing optical waveguide such that said light diffusing optical waveguide is sandwiched between said plurality of white LEDs and said light guide plate, said plurality of white LEDs emitting a white light that propagates through the light diffusing optical wave guide toward a side of said light guide plate; a single color LED disposed on a different side of said light diffusing optical waveguide than a side of said light diffusing optical waveguide on which said plurality of white LEDs are disposed, said single color LED emitting a single color light that propagates through said light diffusing optical waveguide to said light guide plate; and a light diffusing portion disposed on a portion of said light diffusing optical waveguide where the plurality of white LEDs are not disposed for diffusing the single color light as the single color light propagates through said light diffusing optical waveguide, wherein the single color light from the single color LED is directed to turn into the light guide plate at the light diffusing portion disposed on said light diffusing optical waveguide, wherein the portion of said light diffusing optical waveguide on which said light diffusing portion is disposed does not oppose the side of said light diffusing optical waveguide on which the white LEDs are disposed, and wherein said light diffusing optical waveguide has grooves formed in a side thereof facing said light guide plate, said grooves being spaced more closely at a center portion of said light diffusing optical waveguide than at the side on which the single color LED is disposed.