Novel method for preparing high-power white LED with low color temperature and high color rendering property

Abstract

The invention discloses a method for preparing a high-power white LED with low color temperature and high color rendering property. In the method, fluorescent powder is excited by adopting an InGaN-based blue LED chip, wherein the fluorescent powder is a mixture of yellow fluorescent powder, green fluorescent powder and orange red fluorescent powder; both peak values of excitation spectra of the yellow fluorescent powder and the green fluorescent powder are matched with an emission spectrum of the InGaN-based blue LED chip; and the peak value of the emission spectrum of the green fluorescent powder is matched with the excitation spectrum of the orange red fluorescent powder. The yellow fluorescent powder and the green fluorescent powder are excited by the emitted light of the InGaN-based blue LED chip respectively, and the orange red fluorescent powder is excited by the emitted light of the green fluorescent powder, so that the method improves the photoluminescence conversion efficiency of the fluorescent powder. By reasonably regulating the ratio of the fluorescent powder, the method can ensure that the spectrum of the white LED consists of blue light, yellow light, green light and orange red light and has high continuity and high balance, and high luminous efficiency and the high color rendering property of the high-power white LED at a low color temperature are realized.

Description

technical field [0001] The invention relates to a low color temperature and high color rendering white light LED, in particular to a new method for preparing a low color temperature high color rendering high power white light LED. Background technique [0002] With the improvement of light-emitting diode (LED) chip and packaging technology, white LED is gradually favored by people as a general lighting source. It has a series of advantages such as low voltage, low power consumption, high reliability, and long life. It has been widely used in LED street lamps, LED lamps and other fields. It is a new green light source that complies with the national "energy saving and emission reduction" policy. In September 2009, the European Union took the lead in promulgating the policy of prohibiting the sale of incandescent lamps, and various countries have also announced the progress of the ban, making white LEDs a big step forward in general lighting, especially indoor lighting. Howev...

AI Technical Summary

Problems solved by technology

Using InGaN-based blue LED chips to excite YAG:Ce 3+ Yellow phosphor, difficult to achieve low color temperature below 4000K and high color rendering of Ra>80 white LED

In order to change the shortage of monochromatic phosphors, Zheng Daishun and others used blue LED chips to excite yellow and red phosphors to obtain white LEDs. The Tc and Ra were 3200K and 83.2, respectively, but because the emission peak wavelength of blue LEDs is different from that of red phosphors The excitation spectrum does not match, resulting in the luminous flux and luminous efficiency of the device being only 14.1lm and 12.72lm / W

The research of Wu Haibin, Rong-JunXie et al. also shows that the luminous efficiency of white LEDs with low color temperature below 4000K is low (<20lm / w), which is due to the low conversion efficiency of yellow and red phosphors excited by blue LEDs.

In addition, Naoki Kimura and others successively used blue LED chips to excite three or more kinds of phosphors to prepare white LEDs with low color temperature and high color rendering, but there is still the problem of low conversion efficiency of phosphors

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