The impacts of red-emitting phosphor Mg8Ge2O11F2:Mn4+ on the color rendering index of convex-dual-layer remote phosphor WLEDs at 5600 K

<span>The white-light light-emitting diode (LED) is a semiconductor light source that usually has one chip and one phosphor layer. Because of that simple structure, the color rendering index (CRI) is really poor. Therefore, structure with double layer of phosphor and multiple chips has been studied with the phosphorus proportions and densities in the silicone are constantly changed to find the best option to improve optical properties. In research, we use red phosphor Ca5B2SiO10:Eu3+ layer to place above the yellow phosphor one, and both of them have a convex design. Then, the experiments and measurements are carried out to figure out the effects of this red phosphor as well as the convex-double-layer remote phosphor design on the LED’s performances. The measured results reveal that the light output is enhanced significantly when using convex-dual-layer structure instead of the single-layer design. Additionally, the Ca5B2SiO10:Eu3+ concentration benefits CRI and CQS at around 6600 K and 7700 K correlated color temperature (CCT). Yet, the lumen output shows a slight decline as this red phosphor concentration surpass 26% wt. Through the experiments, it is found that a double layer of chip and double phosphorus is the best structure which could support the quality of CRI and luminous flux.</span>

Download Full-text

A red-emitting phosphor K2[MoO2F4]•H2O:Mn4+ for warm white light-emitting diodes with a high color rendering index

Materials Research Bulletin ◽

10.1016/j.materresbull.2019.110675 ◽

2020 ◽

Vol 122 ◽

pp. 110675 ◽

Cited By ~ 1

Author(s):

Yan Liu ◽

Hong Li ◽

Shu Tang ◽

Qiang Zhou ◽

Kaimin Wang ◽

...

Keyword(s):

White Light ◽

Light Emitting Diodes ◽

Light Emitting ◽

Warm White Light ◽

Color Rendering Index ◽

White Light Emitting Diodes ◽

Color Rendering ◽

Red Emitting Phosphor

Download Full-text

Selection of Remote Phosphor Led Packages for Improving Luminous Flux

Journal of Advanced Engineering and Computation ◽

10.25073/jaec.202042.259 ◽

2020 ◽

Vol 4 (2) ◽

pp. 118

Author(s):

Ming Jui Chen ◽

Hsiao-Yi Lee ◽

Nguyen Doan Quoc Anh ◽

Thi Phuong Loan Nguyen ◽

Van Tho Le

Keyword(s):

White Light ◽

Layer Structure ◽

Luminous Flux ◽

White Leds ◽

Creative Commons ◽

Triple Layer ◽

Study Results ◽

Remote Phosphor ◽

Color Rendering Index ◽

Color Rendering

In this paper, the first issue presented and analyzed by several experiments is the influence of the distance between phosphor layers in the dual-layer and triple-layer remote package on luminous flux and color rendering property. During the simulation, it was realized that it was possible to create a suitable distance to create higher quality white light-emitting diodes (WLEDs) by adjusting the distance between the phosphor layers. According to the study results, 0.1 mm is the most reasonable distance between two phosphor layers so that the performance of the multi-chip white light LED (MCW LED) can get the best optimal effect. Through a series of experiments, it has been proved that the efficiency of the two-layer structure gives optical properties higher than the three-layer structure related to distance. The highest achievable lumen output is 0.6 mm for the triple-layer structure and 0.1 mm for dual-layer structure. Meanwhile, the color rendering index changes insignificantly when the distance increases. The triple-layer package is not practical for high-power white LEDs due to the high cost and low conversion efficiency. The dual-layer remote phosphor package with a 0.1 mm phosphorus gap is the optimal structure of WLED in improving luminous efficiency and color rendering index. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

Download Full-text