Study of Phosphor Thermal-Isolated Packaging Technologies for High-Power White Light-Emitting Diodes

Reliability and Lifetime Prediction of Remote Phosphor Plates in Solid-State Lighting Applications Using Accelerated Degradation Testing

“…[1][2][3][4] It has been already shown that thermal stress degrades the luminous output of the devices. [15][16][17][18][19][20][21][22][23] This study aims at studying the effect of blue light intensity together with thermal stress on the lumen depreciation and the reliability of LED-based products and on the acceleration of optical degradation. The phosphor layer can itself be a heat generator as the input power increases and becomes more important if there is not a sufficient thermal path for heat dissipation.…”

“…[1][2][3][4][5][6][7][8][9][10] In this type of LED, the phosphor is either coated on the chip or mixed with the lens disc. [11][12][13][14][15][16][17][18][19][20][21][22] The spatial distribution of phosphor in white LED lamps strongly influences the colour uniformity and the efficiency of the light source. In proximate phosphor distributions, the phosphor is located in close proximity to the semiconductor chip, while in the remote phosphor configuration, there is a distance between the phosphor layer and the chip.…”

“…Application of both thermal stress and light intensity in a HAST set-up is expected to make the kinetics of degradation much faster. There are many papers regarding the reliability of LED systems [13][14][15][16][17][18][19][20][21] under thermal stress; however, there is limited information available about the effects of combined blue light intensity and thermal stress on the ageing and the reliability of remote phosphors. In this study, the effects of both stress factors, applied in the HAST set-up, are studied.…”

Effects of Graphene Monolayer Coating on the Optical Performance of Remote Phosphors

“…Numerous investigations have been performed on various parts of LED-based products; however, not much has been done on the lens/remote phosphors of the LEDs. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Recent reliability studies [14][15][16][17][18][19] have shown that the optical degradation of white LED products is mainly due to the aging of the encapsulants/lens. The encapsulants/lens are mainly used to prevent thermal shock and mechanical stress as well as humidity-induced corrosion.…”

“…They lead to a decrease in the transparency of encapsulants and also a decrease in the LED light output. 9 Although various studies [13][14][15][16][17][18][19] have been performed to reduce the thermal and light degradation of bisphenol-A-polycarbonate (BPA-PC), there are still many challenges to overcome, particularly when it comes to the design and production of encapsulant/lens made by BPA-PC. High heat conductivity, as well as light and heat transparency are really important for encapsulant/lens materials in the LED package.…”