光栅刻划机直线度误差补偿的研究

Research on Straightness Error Compensation of Grating Ruling Machine

中阶梯光栅是一种特殊的衍射光栅,它以高的衍射级次和大的衍射角来工作,具有高分辨率、全波闪耀等特性。已广泛应用于高端光谱仪器之中,极大地促进了航天航空、天文、医疗、军事、环境等尖端科技的发展。但是专业的刻划系统需要定制,价格昂贵。使用已成熟的超精密加工设备来加工中阶梯光栅,可以大大降低中阶梯光栅母版的制备成本。超精密单点金刚石车床制备中阶梯光栅时,系统直线度不好,存在较大的累积误差,导致中阶梯光栅衍射波前较差,达不到制备要求。为了减小超精密单点金刚石车床固有的直线度误差,对超精密单点金刚石车床进行了误差补偿。首先,以累积误差曲线为依据进行第一次补偿。实验结果表明,当补偿系数为0.75~0.85时,此时衍射波前的PV(峰谷值)值在约400 nm,一次直线度补偿效果到达极限。然后,以闪耀级的衍射波前曲线为依据进行第二次直线度补偿,二次补偿后的衍射波前PV值为约83 nm。补偿后的结果表明衍射波前得到大幅改善,有利于提高所制备光栅的质量,在光栅实际刻划中具有指导作用。

Echelle grating is a kind of special diffraction grating.Working with high diffraction orders and big diffraction angle,which has the advantages of high resolution and full wave shining.It has been widely used in high-end spectrum instrument,which greatly promoted the development of aerospace,astronomy,medical,military,environment and other cutting-edge technology.However,professional scoring system needs to be customized,and the price is very expensive.The use of sophisticated ultra precision machining equipment to process in the ladder grating can greatly reduce the preparation cost of the mother plate of the ladder grating.Due to the bad straightness and high accumulative error of ultra precision single point diamond lathe,it can＇t satisfy the demand of preparation when preparing the echelle grating,casuing the bad diffraction wave front.In order to reduce the straightness error,this paper comes up with the error compensation for the single point diamond lathe.Firstly,we make the first compensation based on the accumulative error curve.When the compensation ratio is 0.75 to 0.85,the peak valley value（pv） of the diffraction wave front is about 400 nm,reaching its greatest effect of the first straightness compensation.Secondly,we make the straightness compensation according to the diffraction wave front curve of the blazed order.The pv of the diffraction wave front is about 83 nm.The results show that the diffraction wave front is greatly improved which is beneficial to improve the quality of the grating,and has a guiding role in the actual grating characterization.