Lens composition of light emission diode device, LED device, backlight unit and liquid crystal display comprising the same

A light emitting diode (LED) device for an LCD comprising:

• lead frames composed of a cathode and an anode, respectively;
• a chip positioned on the cathode lead frame;
• a metal wire connecting the chip and the anode lead frame;
• and
• a lens comprising a lens composition comprising a copolymer represented by the formula 1 and having a weight average molecular weight of about 5,000 to about 500,000:
• wherein R1 and R2 independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or —COOR3 group in which R3 represents a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, R4 and R5 independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, the ratio n/n+m ranges from about 0.3 to about 0.995, and the ratio m/n+m ranges from about 0.005 to about 0.7, wherein the lens surrounds the chip, having one end of either lead frame exposed outside.

A backlight unit for an LCD comprising:

• a light source comprising an LED device having lead frames composed of a cathode and an anode, respectively, a chip positioned on the cathode lead frame, a metal wire connecting the chip and the anode lead frame, and a lens surrounding the chip, having one end of either lead frame exposed outside, and comprising a lens composition comprising a copolymer represented by the formula 1 and having a weight average molecular weight of about 5,000 to about 500,000:
• wherein R1 and R2 independently represent a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms or —COOR3 group in which R3 represents a linear, branched or cyclic alkyl group having 1 to 10 carbon atoms, R4 and R5 independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, the ratio n/n+m ranges from about 0.3 to about 0.995, and the ratio m/n+m ranges from about 0.005 to about 0.7;
• a light guide plate positioned above the light source;
• and
• a reflection plate disposed between the light guide plate and the light source and exposing the LED device.