Novel adjustable low-color-temperature high-color-rendering high-power white light LED method

Abstract

The invention discloses a novel adjustable low-color-temperature high-color-rendering high-power white light LED method. Fluorescent powder is excited by InGaN-based blue light LED chips and is a mixture of yellow fluorescent powder, green fluorescent powder and orange red fluorescent powder, peak values of excitation spectra of the yellow fluorescent powder and the green fluorescent powder are matched with emission spectra of the InGaN-based blue light LED chips, and a peak value of the emission spectra of the green fluorescent powder is matched with excitation spectra of the orange red fluorescent powder. By means of the novel adjustable low-color-temperature high-color-rendering high-power white light LED method, the yellow fluorescent powder and the green fluorescent powder are respectively excited by emission light of the InGaN-based blue light LED chips, the orange red fluorescent powder is then excited by emission light of the green fluorescent powder, and therefore the photoluminescence conversion efficiency of the fluorescent powder is improved. The proportions of the fluorescent powder are reasonably adjusted, white light LED spectra can be composed of blue light, yellow light, green light and orange red light and have good continuity and good balance, and the high luminous efficiency and the high color rendering of high-power white light LEDs are further achieved under the low-color-temperature condition.

Description

technical field [0001] The invention relates to a low color temperature and high color rendering white light LED, in particular to a method for adjusting a low color temperature high color rendering high power white light LED. Background technique [0002] With the advancement of light-emitting diode (LED) chips and packaging technology, white LEDs are gradually gaining popularity 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 banning the sale of incandescent lamps, and various countries have also announced the process of banning the sale, making white LEDs a big step forward in general lighting, especially indoor lighting. H...

AI Technical Summary

Problems solved by technology

Using InGaN-based blue LED chip to excite YAG:Ce3+ yellow phosphor, it is difficult to realize white LED with low color temperature below 4000K and high color rendering of Ra > 80

In order to change the shortage of monochromatic phosphors, Zheng Daishun et al. used blue LED chips to excite yellow and red phosphors to obtain white LEDs, whose 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 et al. 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.

Images