基于单色LED的日光光谱拟合

Solar Spectral Fitting Based on Monochrome LED

在照明领域中,LED已被证明是一种很有前途的人造光源,其光谱可以用来合成日光光谱。目前通过不同种类的LED合成日光光谱的关键问题是如何从LED数据库中选择LED型号和确定各型号LED的工作参数。针对这一问题,科学家们提出了通过各种数学模型来表示LED的光谱功率分布,如高斯函数、洛伦兹函数、logistic功率峰函数等。这些数学模型可以准确地反映出LED的非线性光谱特征,包括峰值波长、半高宽、红移等。但是通过数学光谱模型模拟的LED光谱与真实的LED光谱并不完全相同,通过数学光谱模型模拟的LED光谱曲线都是轴对称的。然而,真实的蓝色和绿色LED光谱曲线在短波长的一面更陡,在长波长的一面更缓,红色LED光谱曲线则相反。基于现有的多个LED的基础上提出了一个新的模拟日光光谱的方法。通过设计一个滤光片和调节各个现有的LED光源的辐射量权重(LED光源的辐射量权重为当前LED光源的辐射量与该LED的最大辐射量的百分比)来进行仿真实验,以此模拟出一个新的光源,使其光谱与日光光谱相接近。即将一个滤光片放置在多个LED的混合光源下,通过滤光片的光谱透射率和各个LED光源的辐射量权重来限制光源的光谱,使得修正后的多个LED混合光源的光谱尽可能的接近日光光源光谱。因工业要求需要对滤光片的光谱透射率曲线进行平滑约束。最后通过优化后的滤光片的光谱透射率求出各个LED光源的辐射量权重的最小二乘解,从而得到各个最优的LED光源的辐射量权重。通过仿真实验,最后该方法得到的模拟日光光源的相关色温(CCT)为6492 K,目标光源的相关色温为6503 K。模拟日光光源光谱与日光光谱的拟合优度(R 2)为0.9926。该方法对基于LED的日光光谱拟合的研究有重要的参考价值。

In the photovoltaic field,LED has been proven to be a promising artificial light source,and its spectrum can synthesize sunlight spectrum.At present,the key problem of synthesizing the sunlight spectrum through different kinds of LEDs is how to select led models from the LED database and determine the working parameters of each model of LED.To solve this problem,scientists have proposed various mathematical spectral models to express the spectral power distribution of LED,such as the Gaussian function,Lorentz function,logistic power peak function and so on.These mathematical models can accurately reflect the nonlinear spectral characteristics of LED,including peak wavelength,FWHM,redshift and so on.However,the LED spectrum simulated by the mathematical spectrum model is different from the real led spectrum.The LED spectrum curve simulated by the mathematical spectrum model is symmetrical.However,the spectral curves of real blue and green LEDs are steeper on the short wavelength side and slower on the long wavelength side,while the spectral curves of red LEDs are the opposite.Based on the existing LED light sources,this paper proposes a new method to simulate the solar spectrum.The simulation experiment is carried out by designing a filter and adjusting the radiation weight of each existing LED light source(the radiation weight of an LED light source is the percentage of the radiation of the current LED light source and the maximum radiation of the LED),to simulate a new light source and make its spectrum close to the sunlight spectrum.That is,one filter is placed under the mixed light source of multiple LEDs,and the spectrum of the light source is limited by the spectral transmittance of the filter and the radiation weight of each LED light source so that the spectrum of the modified multiple LED mixed light sources is as close to the spectrum of the daylight light source as possible.Due to industrial requirements,it is necessary to smooth and constrain the spectral transmittance curve of the filter.Finally,through the spectral transmittance of the optimized filter,the least square solution of the radiation weight of each LED light source is obtained to obtain the radiation weight of each optimal LED light source.Through the simulation experiment,the correlated color temperature(CCT)of the simulated sunlight light source obtained by this method is 6492,and the correlated color temperature of the target light source is 6503.The correlation index(R 2)between the simulated sunlight source and the sunlight spectrum is 0.9926.The method of this paper provides an important reference value for the research of solar spectrum fitting based on LED.