Regularized parametric model of the angular distribution of the brightness factor of a rough surface

While the remote phosphor structure is not an appropriate solution for WLED color uniformity, it is more advantageous for the luminous output of WLED than the conformal phosphor or in-cup phosphor structure. Acknowledging the ability of the remote phosphor structure, many studies have been carried out to surmount the color quality disadvantage of this structure. A dual-layer remote phosphor configuration is proposed in this research paper to acquire better color quality for WLEDs through heightening the color rendering index (CRI) and the color quality scale (CQS). The color temperature of the WLED packages this study is 8500 K. By inserting a layer of green CaSO4:Ce3+,Mn2+ or red LiLaO2:Eu3+ phosphor on the yellow YAG:Ce3+ phosphor layer, the phosphor structure configuration can be constructed. Then, to get the best color quality, the concentration of added phosphor LiLaO2:Eu3+ would be changed. The findings showed the rise of CRI and CQS along with the LiLaO2:Eu3+, which implies the influence of LiLaO2:Eu3+ to the growth of red light components within WLEDs packages. The greater the concentration of LiLaO2:Eu3+ is, the more the CRI and CQS increase. Meanwhile, the luminous flux gains from the green phosphor CaSO4:Ce3+,Mn2+. Nevertheless, the luminous flux and color quality would decrease if the concentrations of both red LiLaO2:Eu3+ and green CaSO4:Ce3+,Mn2+ phosphors reach a certain corresponding level. Centered on the Mie-scattering theory and the law of Lambert-Beer, this result is illustrated. The findings in this research are vital references for manufacturing WLEDs with higher white light performance.

Section: Computation and Discussionmentioning

confidence: 99%

Improving the optical efficiency of white light-emitting diodes based on phosphor-in-glass by a dual-layer remote phosphorus structure with the application of LiLaO2:Eu3+ and CaSO4:Ce3+, Mn2+

Tien

2021

“…Furthermore, when concentrations increased, the gaussian regions correlative magnitude lay at the values of 310 and 400 nm in stimulation spectrum increased higher over the other two regions, reflecting a rise in Eu 2+ occupancy at smaller Ca(1) sites. However, as the concentration of Eu 2+ increased to 3.0 mol%, both the stimulation and emission maxima redshifted slightly, which is assumed to be due to increased Eu 2+ crystalline sector breaking in the sites of Ca(2) [24], [25].…”

Section: Computational Simulation 21 X-ray Diffraction Analysis For C...mentioning

confidence: 95%

Using liquid phase precursor method to create a high-efficiency Ca2SiO4:Eu2+ green-emitting phosphor

Huu

Thi

2022

A standard solid-state reaction (SSR), a new fluid phase preparatory method utilizing LPP-SiO2(sol), and a water-based soluble silicone compound were employed to manufacture green Eu2+-based Ca2SiO4 phosphors liquid phase precursor (LPP-WSS). The generated phosphors feature large excitation spectra in the range of 225–450 nm and a strong green emission reaches the peak value at 502 nm owing to a 4f65d1→4f7(8S7/2) transition of Eu2+. These samples burned at 1100 1C produce the highest luminous intensity. The luminous properties of phosphors, which are manufactured by the liquid phase precursor LPP-WSS technique, were investigated at the range of 0.1-5.0 mol percent of Eu2+, with the maximum emission density observed at the value of 3.0 mol percent of Eu2+. The phosphors produced by the LPP-WSS technique exhibited a more uniform phase dispersion and higher luminous strength than those produced using the other procedures, according to a detailed report based on numerous characterizations. As a result, Ca2SiO4:Eu2+ has an indisputable possibility in white light-emitting diodes WLEDs and fluorescent lighting.

“…KN is the diffuser unit number for a single diffuser concentration and can be determined as below [25], [26]: (6) Where M(r) is the diffusive unit's mass distribution, proposed by the equation [27]: (7) ρdiff(r) and ρphos(r) are the density of diffuser and phosphor crystal. According to Mie theory, Csca could be acquired by the calculation below [28]: (8) Where k=2π/λ, and an and bn are computed as follows:…”

Section: Scattering Computationmentioning

confidence: 99%

Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K white LEDs

Thi

That

2021

SiO2 nano-particles have been examined in a distant phosphor structure for the elevated luminous quality and better consistency of white light-emitting diodes with angular-dependent associated color temperature (CCT). The luminous scattering ability could be increased by applying SiO2 nano-particles contain silicone to the outside of the phosphorus coating. In specific, the strength of blue light at wide angles is increased and differences in CCT can be minimized. In addition, owing to the sufficient refractive indices of silicone-containing SiO2 nanoparticles between the air and phosphorus layers, the luminous flux was improved. This new configuration decreases angular-dependent CCT deviations in the range of -700 to 700 from 1000 to 420 K. In comparison, at a 120 mA driving current, the rise of lumen flux increased by 2.25% relative to an usual distant phosphor structure without SiO2 nano-particles. As a result, in a distant phosphor structure, the SiO2 nano-particles could not only enhance the uniformity of illumination but also enhance the output of light.