光學(xué)系統的用法和樣例：
例句
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（聚焦區）無(wú)限遠與光學(xué)系統（如照像鏡頭）有關(guān)的一個(gè)范圍，表示距離是如此之遠，以至于從在這一距離的物體上反射回來(lái)的光可以視為平行光線(xiàn)
A range in relation to an optical system, such as a camera lens, representing distances great enough that light rays reflected from objects within the range may be regarded as parallel.
