How to use the Multi-chip combination and Multiple quantum well recombination to manufacture the white LEDs?

 l  Multi-chip combination

White LED, which encapsulates semiconductor chips with various colors, is called multichip combination white light LED. Tricolor RGB composite white light is the most representative way to obtain white light. The technology requires stable driving current for each LED chip and good heat dissipation of the packaged samples so that the white light emitted by the chip is stable. Compared with white LED with phosphor, the energy loss caused by stocks frequency shift is avoided, and the luminous efficiency and color rendering index (Ra > 95) are higher than that of white LED using phosphor. In addition, the color index of white LED can be adjusted with the wavelength and intensity of LED chip.

The main shortcomings of this approach include:

1.The change of light color may be inconsistent. The stability of white light is greatly affected by the fluctuation of current at both ends of the loaded LED, the difference of chip temperature, and the inconsistency of the decay rate of the chip with time. For this reason, LED chips of various colors need to be designed one by one to compensate and adjust the function of the complex feedback circuit.

2.Higher cost:

It is difficult to overcome the heat dissipation problem of the chip. For example, the thermal resistance of RGB trichromatic LED encapsulation is three times that of phosphors. Using new technology to fabricate multichip white light LED is a way to solve the problem of heat dissipation, but this will increase the production cost, which is not conducive to practical application and marketization direction.

l  Multiple quantum well recombination

Different semiconductor materials are grouped side by side to form a quantum well with quantum confinement effect.

The photoluminescence chip doped with different impurity can obtain multiple band gap energy levels, thus forming different quantum levels.through these different quantum wells emitted by a variety of colors of photons can get white. The white LED produced by this method is still in the laboratory research stage because of its harsh technical requirements and no commercial application.

Allicdata Electronic specialize in the production of white LED,color LED.

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