What methods are used to achieve white LEDs?
At present, there are three main methods for LED to achieve white light:
(1) Synthesize white light through LED red, blue and yellow three-color multi-chip combination;
Advantages: high efficiency, controllable color temperature, good color rendering.
Disadvantages: The different light decay of the three primary colors leads to unstable color temperature, complicated control circuit and high cost.
(2) The blue LED chip excites the yellow phosphor, and the white light is synthesized by the blue light of the LED and the yellow-green light emitted by the phosphor.
In order to change the color rendering performance, a small amount of red phosphors can also be added to it, or an appropriate amount of green and red phosphors can be added at the same time;
Advantages: high efficiency, simple preparation, good temperature stability and good color rendering.
Disadvantages: poor consistency, color temperature, angle changes.
(3) The near-ultraviolet LED chip excites the phosphor to emit three-color synthetic white light.
Advantages: good color rendering, simple preparation.
Disadvantages: At present, the efficiency of LED chips is low, there is a problem of ultraviolet light leakage, and the problem of temperature stability of phosphors needs to be solved.
