Combining near-field hyperspectral imaging and far-field spectral-angular distribution to develop mid-field white LED optical models with spatial color deviation

Abstract

The integration of spatial distribution of light intensity and color in the midfield is instrumental for LED optical design. On the basis of this rationale, we proposed an accurate and convenient method for developing white LED optical models. Near-field hyperspectral images and far-field spectral-angular distributions were integrated to illustrate changes in spatial light intensity and color distribution in the mid-field, to the exclusion of the absorption, conversion, and scattering of phosphors. The corresponding optical models were developed for three LED samples under different packaging conditions. Their normalized cross-correlation values for spatial light intensity and correlated-color-temperature distribution between simulation and measurement averaged as high as 0.995 and 0.99 respectively, which validated the accuracy and feasibility of the proposed method.

Spectral near field data of LED systems for optical simulations

“…Figure 1: Examples of spectrally varying sources and optical system which lead color non-uniformities (published under CC BY-SA 4.0 from [1]). Recent methods to model or measure spectral ray data were proposed during the last years [12][13][14][15][16][17][18]. Most of them combine conventional ILMD-based (imaging luminance measurement device) near field goniophotometry with different optical filters and spectral measurements [12][13][14][15][16].…”