Patent ID: 7297380

Claim:
A light-diffusing film comprising: about 90 wt. % to about 99.999 wt. % polycarbonate, wherein the polycarbonate comprises a yellowness index of about 0.8 to about 1.5 as measured in accordance with ASTM E313-73 (D1925); about 0.001 wt. % to about 3 wt. % light-diffusing particles; and wherein weight percents are based on a total weight of the light-diffusing film; wherein the light-diffusing film comprises a light transmission of about 45% to about 65% as measured in accordance with ASTM D1003-00, and a hiding power of 0 to about 0.5 that is mathematically described by the following equation: Hiding ⁢ ⁢ power ⁢ ⁢ ( % ) =  1 - ∑ i = 1 n - 1 ⁢ L i ⁡ ( on ) ∑ j = 1 n - 1 ⁢ L j ⁡ ( off )  × 100 wherein: L i (on) is luminance above i th cold cathode fluorescent lamp, L j (off) is luminance at a midpoint between cold cathode fluorescent lamp j and cold cathode fluorescent lamp j+1, and n equals number of CCFL lamps; and wherein the light-diffusing film has a 13 points average luminance that is greater than a 13 points average luminance of a polycarbonate film, as determined by a 13 points test using a Topcon BM-7 instrument, wherein the polycarbonate film comprises about 3.5 wt % acrylate particles based on a total weight of the polycarbonate film, and the polycarbonate film has a thickness of 2 millimeters and a transmission of 50.4% as determined in accordance with ASTM D1003-00 and as measured with instrument Macbeth 7000A, D65 light source illuminant, 10° observer.