Composite white light LED and preparation method

The invention discloses a composite white light LED which comprises a substrate, an LED chip and a transparent casing. The bottom of the LED chip is fixed to the surface of the substrate. The upper part of the substrate is sleeved by a transparent shell. The upper part of the LED chip is covered with phosphor colloid. The inner surface of the transparent shell is attached with a quantum dot film. An air gap is between the quantum dot film and the phosphor colloid. The invention also discloses a preparation method of the composite white light LED. Since the air gap is between the phosphor colloid and a quantum dot shell, the air gap can prevent the absorption effect between quantum dot emitting light and fluorescent powder emitting light, the quantum dot film and a fluorescent powder layer are curved surface topographies, the removal of light energy is facilitated, and thus the light emitting efficiency of the composite white light LED is improved significantly. The operation method is simple, the cost is low, the thicknesses, topographies and compositions of the phosphor colloid and the quantum dot film can be flexibly controlled, thus the composite white light LED with high color performance is obtained, and the composite white light LED is suitable for mass production.