两焦 meaning in Chinese

double energizer

A sample is put on the table which is processed into a inclined plane on the filmed plane , and two interfaces of a film are focalized , then the thickness is read out that is a difference between the heights of two interfaces of a film
将实验样品的覆膜面打磨成斜面后平放在金相显微镜样品台上，分别对膜层的两个界面对焦，从对焦旋钮上读出两焦面的高度差即为膜层的厚度。