Number Of LED Chips Research Articles

Thermal management of square light emitting diode arrays: modeling and parametric analysis

PurposeThis study investigates the impact of three parameters such as: number of LED chips, pitch and LED power on the junction temperature of LEDs using a best heat sink configuration selected according to a lower temperature. This study provides valuable insights into how to design LED arrays with lower junction temperatures.Design/methodology/approachTo determine the best configuration of a heat sink, a numerical study was conducted in Comsol Multiphysics on 10 different configurations. The configuration with the lowest junction temperature was selected for further analysis. The number of LED chips, pitch and LED power were then varied to determine the optimal configuration for this heat sink. A general equation for the average LED temperature as a function of these three factors was derived using Minitab software.FindingsAmong 10 configurations of the rectangular heat sink, we deduce that the best configuration corresponds to the first design having 1 mm of width, 0.5 mm of height and 45 mm of length. The average temperature for this design is 50.5 C. For the power of LED equal to 50 W–200 W, the average temperature of this LED drops when the number of LED chips reduces and the pitch size decreases. Indeed, the best array-LED corresponds to 64 LED chips and a pitch size of 0.5 mm. In addition, a generalization equation for average temperature is determined as a function of the number of LED chips, pitch and power of LED which are key factors for reducing the Junction temperature.Originality/valueThe study is original in its focus on three factors that have not been studied together in previous research. A numerical simulation method is used to investigate the impact of the three factors, which is more accurate and reliable than experimental methods. The study considers a wide range of values for the three factors, which allows for a more comprehensive understanding of their impact. It derives a general equation for the average temperature of the LED, which can be used to design LED arrays with desired junction temperatures.

Multi-LED Phase-Shifted OOK Modulation Based Visible Light Communication Systems

The limited modulation bandwidth and the non-linearity nature of LEDs are the key challenges to visible light communication. In general, one LED lamp consists of multiple LED chips. In this letter, these LED chips are used for parallel transmission though multi-LED phase-shifted OOK (MP-OOK) modulation. For MP-OOK, the bandwidth efficiency is approximate N times that of conventional OOK ( N is the number of LED chips). For each branch, the modulation format is OOK. Hence, MP-OOK has a better anti-nonlinearity performance than other high-order modulation formats, such as DC-biased optical orthogonal frequency-division multiplexing (DCO-OFDM). The simulation comparisons between MP-OOK and DCO-OFDM verify these.

The Optimal Design of Multi-Chip White-Light LEDs for Color Uniformity

A multi-chip white-light modeling algorithm for high color rendering index and high color uniformity of surface mounted LED devices is demonstrated. The simulation of white-light LED model, according to the principle of additive color mixture by four color of red, amber, green, blue LEDs and using the commercial software program to perform Monte Carlo ray tracing has been developed. The simulation and experimental results show that the performance can be achieved with a number of LED chips.

Comparison and optimization of light source design schemes for indoor optical wireless communication based on light emitting diode

The existing indoor optical wireless communication systems can not provide good wireless coverage uniformity and are not suitable for commercial applications.Two distributed light design schemes were proposed to solve the above problems,which increased the group number of LED array,and then increased the uniformity of light distribution of every group.The simulation results indicate that with the same number of LED chips,the distributed light design scheme is superior to the traditional one in uniformity of wireless signal coverage and complexity of commercial implementation,and can avoid the coverage valley.