White LED chip and preparation method thereof

Abstract

The invention discloses a white light emitting diode (LED) chip and a preparation method thereof. The white LED chip comprises a blue LED chip with a vertical structure and a yellow LED chip from which a substrate is removed, wherein the blue LED chip and the yellow LED chip are bonded together through a transparent conductive adhesive; an N electrode is formed on the lower surface of the blue LED chip with the vertical structure; and a P electrode is formed on the upper surface of the yellow LED chip from which the substrate is removed. The preparation method of the white LED chip comprises the following steps of: preparing the blue LED chip with the vertical structure and the yellow LED chip; connecting the yellow LED chip together with the blue LED chip through the transparent conductive adhesive; removing the substrate and a buffer layer from the yellow LED chip; manufacturing the P electrode on a P-type limiting layer of the yellow LED chip from which the substrate is removed; and evaporating electrode metal on the lower surface of a substrate of the blue LED chip to form the N electrode so as to obtain the white LED chip. The white LED chip prepared by the method can directly emit white light, and has the advantages of long service life, high efficiency, stability and the like.

Description

technical field [0001] The invention relates to a structure of a white light emitting diode (LED) and a manufacturing method thereof, belonging to the technical field of white light LEDs. Background technique [0002] White light-emitting diodes (LEDs) are becoming the most potential next-generation lighting source to replace traditional electric light sources because of their advantages of energy saving and environmental protection. The energy consumption of white light LED is only 1 / 8 of incandescent lamp, 1 / 2 of fluorescent lamp, and its life span can be as long as 100,000 hours, which can be described as "once and for all" for ordinary household lighting. At the same time, it can be mercury-free and easy to recycle, which is of great significance for environmental protection and energy saving. [0003] At present, there are two main methods for preparing white light LEDs: 1. Mix LED chips of red, green and blue light colors into white light through the superposition pri...

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Problems solved by technology

The disadvantage is that the deterioration of individual single-color LEDs will lead to impure or uneven light color and unstable color temperature. At the same time, the cost is relatively high and the control circuit is complicated.

2. Blue light or near-ultraviolet LED chips are coated with yellow phosphor powder to obtain white light LEDs. This method of obtaining white light through blue light LEDs has simple structure, low cost, and high technology maturity, so it is most used, but this method exists. The main problem is: the quality of phosphor powder and slight lack of coating thickness will seriously affect its color rendering index, color temperature, light efficiency and light decay, and due to the influence of heat from the LED chip, the phosphor powder will degrade, making the light color of white LEDs The quality and luminous efficiency are greatly reduced

[0005] The blue LED in the above "Single Electrode White LED Based on Secondary Substrate Transfer Technology and Its Preparation Method" uses a non-conductive substrate, and the blue LED substrate must be peeled off, and the blue LED is bonded to the yellow LED, and then Remove the blue light substrate and share the same substrate with the yellow light LED. Because the blue light LED uses a non-conductive substrate and adopts a conduction current process; using a conductive connection metal to conduct current requires a series of cumbersome manufacturing processes; and the metal will Block part of the light, reduce the light-emitting area, and affect the mixing of blue light and yellow light to produce white light, the current spread is uneven, dense under the connecting metal, and the luminous efficiency is low

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