Patent ID: 8371714

Claim:
A LED assembly, comprising: a Fresnel light emitting diode (LED) lens covered over a plurality of LEDs arranged linearly at an equal distance, comprising: an object-side optical surface having a plurality of Fresnel optical surfaces, each of the Fresnel optical surfaces having a zone area having a plurality of drafts with vertical shape, the plurality of Fresnel optical surfaces corresponding to the plurality of LEDs and arranged linearly at an equal distance so that each central axis formed by a center of each LED connected with a center of each corresponding Fresnel optical surface being parallel to one another; and a source-side optical surface; wherein the light emitted from the plurality of LEDs passes through the zone area of each of the Fresnel optical surfaces and a quasi-circle distribution pattern of the light is formed, and the Fresnel optical surface satisfying following conditions: 0.7 ⁢ < _ ⁢ f s r n ⁢ < _ ⁢ 2.2 0.1 ⁢ < _ ⁢ ( N d ⁢ ⁢ 2 - 1 ) ⁢ d 2 f s ⁢ < _ ⁢ 1.25 wherein f s is effective focal length of the Fresnel LED lens, r n is radius of a last zone of each the Fresnel optical surface, d 2 is thickness of the Fresnel LED lens on the central axis, and N d2 is refractive index of the Fresnel LED lens, and a circuit board; the improvement comprises the plurality of LEDs are arranged linearly at an equal distance on the circuit board so that a central axis formed by a center of each LED connected with a center of each corresponding Fresnel optical surface is parallel to one another; the LED assembly satisfies following condition: 0.8 ≤ κ = ϕ y ϕ x ≤ 1.25 wherein 2φ x is an angle of the place where light intensity is half of highest light intensity in the X direction of the light emitted from the Fresnel LED lens, and 2φ y is an angle of the place where light intensity is half of highest light intensity in the Y direction of the light emitted from the Fresnel LED lens.