各位大大，最近我在看一篇二區(qū)的論文，題目是Grating_micro-dot_patterned_light_guide_plates_for_LED_backlights，Seung Ryong Park，2007。作者在里面提到，團(tuán)隊(duì)的導(dǎo)光板設(shè)計(jì)理念是通過在導(dǎo)光板上表面刻正弦型光柵，使得光以衍射-1級(jí)主級(jí)大出射，如圖所示。那么在作者所希望達(dá)到的出射情況（摘自原文）“when δi=0, all diffracted orders are located in the x-o-z plane as shown in Fig. 2(b). This grating diffraction geometry is referred to as classical “in-plane diffraction.” Under this condition with a sufficiently large incident inclination angle (typically larger than the critical angle), it is possible to make the forward diffracted zero-order vanescent and only the -1st diffracted order to be vertically (in the z-axis direction) out-coupled into air by suitable choice of the grating period”時(shí)，這個(gè)大于臨界角的入射角光線竟然不會(huì)繼續(xù)在導(dǎo)光板內(nèi)全反射，而是發(fā)生了衍射，這里我覺得矛盾[了。既然滿足全反射的條件卻不發(fā)生全反射，為什么呢？ lb'GXd