Comparison of calcium carbonate and titania particles on improving color homogeneity and luminous flux of WLEDs

Abstract

In this paper, the experiments on phosphor-converted LEDs (pc-LEDs) with a correlated color temperature (CCT) of 8500K has been conducted with the scattering enhancement particles (SEPs) to achieve the higher color uniformity and emitted luminous flux of pc-LEDs. Moreover, this paper also introduced about choosing scattering enhancement particles (SEPs), including calcium carbonate (CaCO3) and titania (TiO2), and compared these particles' properties by adding them into the yellow Y3Al5O12:Ce 3+ phosphor compounding. Afterward, the LightTools program was applied to illustrate the optical simulation, and obtained results was analyzed and verified by applying the Mie-scattering theory. The scattering coefficients, the anisotropic scattering, the reduced scattering, and the scattering amplitudes at 455 nm and 595 nm are included in the scattering computation of SEPs. According to researched results, among the SEPs, TiO2 particles result in the highest value of color uniformity. However, a rise in their concentration is the cause of a sharp decline in luminous flux. Meanwhile, CaCO3 particles show the ability of reducing the deviated level in correlated color temperature by 620K if there is employed 30% of CaCO3 concentration. Hence, CaCO3 particles are the recommendation for achieving higher chromatic homogeneity and lumen output.

Comparison between SEPs of CaCO3 and TiO2 in phosphor layer for better color uniformity and stable luminous flux of WLEDs with 7,000 K

“…To analyze the change in luminous efficiency of WLEDs using CaCO 3 and TiO 2 , the scattering computation applying Mie theory, and the transmitted light power calculation based on Lambert-Beer law, were utilized [25]:…”

The Application of Calcium Carbonate CaCO3 and Titania TiO2 for Color Homogeneity and Luminous Flux Enhancement in PC-LEDs

“…Therefore, this research employs CaCO 3 and TiO 2 , which are frequently used in pc-LED, for the effectiveness in enhancement tests and then compares the results to pick out the most effective SEP. As the results of previous studies suggested, when giving SEPs the right particle size and concentration, they can enhance the lighting performance, therefore, the parameters that show how the SEPs influence the two lighting properties of pc-LED are also computed using Mie scattering theory and presented within the article. In this paper, the WLED package used for experiments has the correlated color temperature of 7000 K, not 8500 K as the previous one [16]. Moreover, the analysis of scattering property was presented and discussed in more detail to demonstrate the enhancement in color uniformity and lumen output.…”