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In phosphor-converted light-emitting diodes (pc-LEDs), phosphor heating can lead to decrease of luminous efficiency or even thermal quenching due to local high phosphor temperature. Phosphor scattering model has been used to calculate the phosphor heat generation. Using this model, there are two methods for heating power estimation, one is the subtractive method and the other is the integral method...
Quantum dots (QDs) have broad prospect in illumination and display in the future with their high quantum efficiency, tunable color in the entire visible range, and excellent color rendering ability. QDs are generally prepared as remote films in white light-emitting diodes(WLED), which gives rise to low light conversion efficiency (LCE). In order to enhance the LCE of QD-converted WLED (QCWLED), a...
Photoluminescence quantum dots (QDs) have been considered as a kind of promising light converting materials with high luminous efficiency, tunable spectrum, and narrow emission. However, the current light conversion efficiency (LCE) of QD films is at a relative low level, which will result in many problems, such as inferior luminous performance, severe self-heating, etc. To enhance the LCE of QD films,...
The color uniformity is a critical index in the evaluation of high quality white light emitting diodes (LEDs). The main factor affecting the color distribution is the state of the phosphor. The secondary factor is the optical structure. This paper analyzes two parameters of the phosphor layer (thickness and concentration) and six optical structures. Results indicate that the structures with reflector...
The state of phosphor will greatly influence the packaging performance such as luminous efficiency, quality of white light and color uniformity. The analysis presents that the small variations of thickness and concentration could significantly influence the light extraction efficiency and the correlated color temperature (CCT). With the increase of thickness and concentration, the light extraction...
High power LED packaging is crucial for the development of solid state lighting. Different optical structures with various states of phosphor will greatly influence the packaging performance such as luminous efficiency, quality of white light and color uniformity. Through the analysis of five different optical structures, it is found that the location of phosphor layer has low impact on the light...
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