Feedback Reversing Design Method for Uniform Illumination in LED Backlighting With Extended Source

In light-emitting diode (LED) direct-lit backlighting application, it is a critical issue that how to design an optical component to achieve high uniform illumination with large distance-height ratio (DHR) and extended sources. A new feedback reversing design method is proposed to solve this problem, including calculation of feedback optimization ratios (FOR) to achieve uniform illumination for extended source and generate the required light intensity distribution freeform lens. According to this method, the uniformity of illuminance of LED extended source array increases from 0.54 to 0.85 significantly. Therefore, this new method provides a practical and simple way for optical design of LED uniform illumination with high DHR and extended source.