Patent ID: 8445932

Claim:
A light-emitting diode device, including: a luminous body has a light-emitting surface and a bottom surface on opposite sides, wherein the luminous body has a first length, a first width and a beam angle; and a colloid covering the luminous body, wherein the colloid includes a first surface and a second surface on opposite sides, the second surface has a second length and a second width, and the colloid has a refractive index, wherein a distance from the light-emitting surface of the luminous body to the second surface of the colloid is smaller than a first value and greater than a second value, the ⁢ ⁢ first ⁢ ⁢ value < the ⁢ ⁢ second ⁢ ⁢ width - the ⁢ ⁢ first ⁢ ⁢ width 2 · cot ⁢ ⁢ α , and the ⁢ ⁢ second ⁢ ⁢ value < the ⁢ ⁢ second ⁢ ⁢ width - the ⁢ ⁢ first ⁢ ⁢ width 2 · cot ⁢ ⁢ v . wherein the sin α=1/the refractive index of the colloid, and the ν is a full width at half maximum of the beam angle.