一、存在问题目前圆光栅的精度采用单项指标的表达方法,即分别规定最大直径间隔误差、均匀性与封闭差。而对这三项误差如何积累,并没有固定的规律与公式。这样在设计时误差分配比较困难,要求过严,刻划难度增加;反之又担心误差积累降低精度。在工艺上容易产生由于一项指标超差,把能用的光栅报废。例如:有二块光栅,一块光栅虽是合格品,但三项指标都已接近极限,另一块直径误差与封闭差都远比 First, the existing problems At present, the accuracy of the circular grating using single indicators of expression, that is, the provisions of the maximum diameter of the gap error, uniformity and poor closure. And how to accumulate these three errors, there is no fixed law and formula. This error in the design of the distribution more difficult, demanding, scratching more difficult; the other hand, worry about the accumulation of errors to reduce accuracy. Easy to produce in the process due to an indicator of tolerance, the use of the grating scrapping. For example: There are two gratings, although a grating is a qualified product, but the three indicators are close to the limit, the other a diameter error and closure are far worse than