Patent ID: 8297772

Claim:
A backlight assembly comprising: a plurality of lamps each having an elongated cylindrical shape that is elongated in a first direction, where the lamps are distributively arranged equidistant from each other along a second direction that is substantially perpendicular to the first direction, each of the cylindrical, elongated and equidistant lamps having a respective major axis extending centrally through its cylindrical shape, the plurality of major axes of the lamps being disposed in a shared plane; a multi-plate diffusion member having a lowest surface disposed parallel to the shared plane of the major axes of the lamps and having at least first and second optical plates, each of the optical plates including a plurality of optical patterns on a surface thereof facing away from the lamps, the optical patterns being extended in the first direction and distributed along the second direction; and a receiving container including a bottom plate and a sidewall formed on an edge of the bottom plate to define a receiving space that receives the lamps and the diffusion member, wherein a first distance (L) between the major axes of adjacent ones of the equidistant lamps is greater than a second distance (D 2 ) between the major axes of the lamps and the lowest surface of the diffusion member so that L is more than two times D 2 but not greater than about four times D 2 , wherein each of the optical patterns has an elliptical arch shape as its cross-section, the elliptical arch shape being defined as a sliced section hypothetically formed by slicing a hypothetical ellipse with a hypothetical line extending parallel to a minor radius (B) of the hypothetical ellipse, wherein a ratio between the minor radius (B) of the hypothetical ellipse and a major radius (A) of the hypothetical ellipse is about 1.4 to about 2.2, wherein a length (P) of a base portion of the elliptical arch shape is about 100 μm to about 300 μm, and a height of the elliptical arch shape is about 50 μm to about 100 μm, and wherein each given one of the first and second optical plates comprises: a main core layer; an upper cladding layer disposed on a first surface of the main core layer and having optical patterns defined thereon for dispersing light to an area above the given optical plate; and a lower cladding layer disposed on a second surface of the main core layer to face a light source, the second surface of the main core layer being opposite to the first surface of the main core layer, wherein a thickness of the main core layer is about 0.8 mm to about 1.5 mm, wherein a thickness of the upper cladding layer is about 50 μm to about 150 μm, and a thickness of the lower cladding layer is about 50 μm to about 150 μm.