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本发明涉及激光衍射测量细微物体和图形尺寸的方法。采用宽带付立叶变换镜头研制的激光测微仪可以测量2～200μm的微小尺寸。本发明根据付立叶镜头的设计要求,为使一般镜头用作副变镜头,提出使镜片按要求弯曲的办法,产生一定的球差来抵消衍射中的非线性偏差。用此方法可作出宽带付立叶变换镜头。用此镜头作成的专用激光测微仪,采用了标准光栅校准的方法,可以对2～200μm的物体进行绝对测量。并采用副瓣对管法可进行动态测量,在2～200μm之间的测量范围内能分辨出0.1％的直径变化。
The present invention relates to a method of laser diffraction measurement of fine objects and patterns. A laser micrometer developed using a broadband Fourier transform lens can measure small dimensions of 2 to 200 μm. According to the design requirements of the Fourier lens, in order to make a general lens used as a sub-lens, a method of bending the lens as required is proposed to generate a certain spherical aberration to cancel the non-linear deviation in diffraction. Use this method to make wide-band Fourier transform lens. The special laser micrometer made with this lens adopts standard grating calibration method and can measure the absolute value of 2 ~ 200μm objects. And the use of side-lobe tube method can be dynamically measured in the range of 2 ~ 200μm can be resolved within 0.1% of the diameter change.