Luminous flux modeling for high power LED automotive headlamp module

Yu, Chaohua; Fan, Jiajie; Qian, Cheng; Fan, Xuejun; Zhang, Guoqi

doi:10.1109/icept.2017.8046695

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…The increase of junction temperature and driving current can deteriorate the luminous efficacy of LEDs. Thus, to predict the luminous flux of LED under different operation conditions, a general luminous flux response surface model [33] is proposed as shown in Eq. (1) (hereby named Model 1):…”

Section: Theories and Methodologies A Luminous Flux Response Surface Modelmentioning

confidence: 99%

“…To understand the luminous efficacy decay mechanism of LED in package level and its long-term degradation mechanism, two experiments are firstly designed in this study for LED packages with four general packaging structures, those are the transient thermal and luminous characteristics measurements and accelerated ageing test. In our previous study [33], a universal luminous flux response surface model was developed to relate the luminous flux with junction temperature and driving current effectively. Therefore, the luminous flux response surface model considering the electric-thermal-luminous coupling effect and the Gaussian based SPD model are proposed in this paper to predict the LED package level luminous efficacy decay and long-term degradation mechanisms respectively.…”

Section: Introductionmentioning

confidence: 99%

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Reliability Assessment of Light-Emitting Diode Packages With Both Luminous Flux Response Surface Model and Spectral Power Distribution Method

et al. 2019

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The inherent luminous characteristics and stability of LED packages during the operation period are highly dependent on their junction temperatures and driving currents. In this paper, the luminous flux of LED packages operated under a wide range of driving currents and junction temperatures are investigated to develop a luminous flux response surface model. The coefficients of the proposed model are further extracted to compare the luminous efficacy decay mechanisms of LED packages with different packaging structures. Furthermore, a spectral power distribution (SPD) method modeled by the Gaussian function is proposed to analyze the long-term degradation mechanisms of all selected LED packages. The results of this study show that: (1) The luminous flux of phosphor converted white LED decreases to accompany with the increase of junction temperature, while that of bare blue LED die keeps relatively stable;(2) The proposed general luminous flux response surface model can be used to predict the luminous flux of LEDs with different packaging technologies accurately, and it can be known from the proposed model that the influences of driving current and temperature on LED chip and phosphor vary with different packaging structures; and (3) The driving current and temperature dependent sensitivities and degradation mechanisms of LED packages can be investigated by using both the luminous flux response surface model and the spectral power distribution method.INDEX TERMS Light-emitting diode, luminous flux response surface model, spectral power distribution, luminous efficacy decay, degradation mechanism.

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Section: Theories and Methodologies A Luminous Flux Response Surface Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reliability Assessment of Light-Emitting Diode Packages With Both Luminous Flux Response Surface Model and Spectral Power Distribution Method

et al. 2019

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“…However, for lighting purposes, several studies have verified a strong variation of the optical efficiency, and consequently, of transmitted optical powers, of HPLEDs when faced with factors such as temperature and aging [12]- [15]. Differences between manufacturing batches, etc., which can further aggravate this scenario making even more ineffective the correction of nonlinearities by eventual factory fixed modeling.…”

Section: Introductionmentioning

confidence: 99%

Predistortion and pre-equalization for nonlinearities and low-pass effect mitigation in OFDM-VLC systems

2019

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The orthogonal frequency division multiplexing (OFDM) transmission has shown promise in applications of visible light communication (VLC). However, the variation of the nonlinearity of the optical power emitted by the high power light emitting diode (HPLED) as a function of current and temperature implies in drastic OFDM-VLC performance degradation. The first part of this work, experimentally confirms and models this degradation due to temperature in a high power white HPLED. The higher attenuation at high frequencies, which is inherent to the HPLED and which is accentuated by the effect of the intrinsic capacitance of the photodiode, is another factor of degradation due to the reduction of the signal-to-noise ratio (SNR) at the receiver for such frequencies. For the mitigation of these effects, we propose a pre-distortion and digital preequalization scheme using a luminous feedback signal in the transmitter module. The system is modeled so that the operating points are mathematically deduced and evaluated by simulations and by an experimental setup. By allowing the linearization of the transmitted light signal and the maintenance of an average SNR in all OFDM subcarriers, the performance improvement is confirmed in comparison with other schemes, such as with non-predistortion, pre-distortion with fixed parameters, and simple post-equalization.

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