etendue
美
英 
例句
As is known in the art, etendue is a function of the area of the emitting source and the solid angle that the light beam includes.
如在本领域中已知的那样,光学扩展性随着发射源的面积和光束所成的立体角而变。
Application of Etendue Theory in LED Projection Display
光束扩展理论应用于LED投影显示系统