Thin film type white light LED chip

Abstract

The invention discloses a thin film type white light LED chip. The thin film type white light LED chip comprises a transparent substrate, a first transparent electrode, a light-emitting structure, a second transparent electrode and a first fluorescent powder layer which are arranged in sequence, wherein the light-emitting structure comprises a light-emitting layer, an electron injection layer anda hole injection layer, the electron injection layer and the hole injection layer are arranged on the two sides of the light-emitting layer, and the total thickness (inverted structure) of the electron injection layer and the second transparent electrode or the total thickness (upright structure) of the hole injection layer and the second transparent electrode is less than the length of the light-emitting wavelength of the light-emitting layer. Through the arrangement of the second transparent electrode, photons emitted by the light-emitting layer are enabled to have an opportunity to permeateinto the first fluorescent powder layer; and the total thickness (inverted structure) of the electron injection layer and the second transparent electrode or the total thickness (upright structure) of the hole injection layer and the second transparent electrode is less than the length of one light-emitting wavelength of the light-emitting layer, so that an evanescent wave generated by total reflection can permeate into the first fluorescent powder layer and is absorbed by the first fluorescent powder layer to emit light, so that the overall external quantum efficiency of the LED chip is improved.

Description

technical field [0001] The invention relates to the technical field of light-emitting diodes (LEDs), in particular to a thin-film white LED chip with high external quantum efficiency and low production cost. Background technique [0002] White light lighting is closely related to the work and life of human beings. White light lighting technology has been greatly developed so far. Among them, white light-emitting diodes (LEDs) have become one of the best choices to replace traditional lighting components (such as incandescent lamps and fluorescent lamps). Using green, Energy-saving and environmentally friendly white LEDs are also the general trend as the main lighting components. Thin-film white LEDs will gradually replace LEDs due to the fact that the thickness of each layer is on the order of nanometers, the amount of materials used is small, and it is also compatible with processes such as scraping and printing, and the cost is lower. Traditional white LEDs emitted by poi...

AI Technical Summary

Problems solved by technology

However, the external quantum efficiency of blue and violet LEDs is low, and the fluorescent quantum efficiency of phosphor powder is less than 100%, which seriously affects the overall efficiency of white LEDs, making the efficiency of white LEDs in the form of "electric + photoinduced" even lower.

In addition, only for plan B, the strong ultraviolet components in its spectrum are harmful to the human body, especially in the case of long-term exposure. Therefore, considering the impact of ultraviolet rays on the human body, the In the current white light implementation, using blue LED chips to excite red and green (or yellow) phosphors (Scheme A) is still the first choice for commercial white LEDs, despite its low efficiency

[0006] see again figure 1 , for solution C, although this method can obtain high-efficiency white LED chips, the device preparation process is complicated, and the entire chip involves more than ten layers of thin film deposition processes, and the cost is very high

For solution D, since the red, green and blue LEDs all require independent driving circuits, the number of driving circuits for each white LED is increased to three sets, and the driving circuit design is complicated, which also requires very high cost, and at the same time sacrifices the horizontal size, usually not used as a lighting element

Due to the problem of preparation cost, the market share of the two white lighting solutions in Scheme C and Scheme D is very low

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