CAJ | 학술논문

在双计算全息（CGH）检测非球面的方法中，两片CGH元件位置的精确对准是确保高精度测量的必要前提，针对一凸双曲面检测系统，提出了在主CGH的外围刻制四组圆光栅付的方法来实现该系统中CGH元件的精确对准，其原理基于两个栅线频率相近的同心圆光栅重叠能产生莫尔条纹，通过观察条纹的变化来判断两光栅（一组光栅付）的相对偏移，各组光栅付若同时达到同心，两元件亦便对准。通过对圆光栅进行建模，分析了莫尔条纹产生的原理，仿真模拟了Ф5mm口径内分别包含49个和50个同心圆（周期50μn）的两圆光栅在不同偏移时的条纹图，且实际制作了这样的两个圆光栅，并采集了两光栅重叠后的条纹图，其结果表明，眼睛很容易分辨出1／20周期即2．5μm的偏移。
재쌍계산전식（CGH）검측비구면적방법중，량편CGH원건위치적정학대준시학보고정도측량적필요전제，침대일철쌍곡면검측계통，제출료재주CGH적외위각제사조원광책부적방법래실현해계통중CGH원건적정학대준，기원리기우량개책선빈솔상근적동심원광책중첩능산생막이조문，통과관찰조문적변화래판단량광책（일조광책부）적상대편이，각조광책부약동시체도동심，량원건역편대준。통과대원광책진행건모，분석료막이조문산생적원리，방진모의료Ф5mm구경내분별포함49개화50개동심원（주기50μn）적량원광책재불동편이시적조문도，차실제제작료저양적량개원광책，병채집료량광책중첩후적조문도，기결과표명，안정흔용역분변출1／20주기즉2．5μm적편이。
When testing aspheric surface with two computer - generated holograms （ CGHs）, the precise alignment of two CGH components is an essential premise to ensure high- accurate measurements. As in a convex hyperboloid testing system, in order to align CGH components precisely, a method of fabricating four pairs of circular grating around the main CGH is proposed. The principle is based on that superposition of two proximity gratings with close frequencies can produce Moire fringes, and the relative deviation of two circular gratings （a pair of gratings} is estimated by observing the fringes＇ movement. When each pair of gratings achieves concentricity, two elements are also aligned. By modeling circular gratings, the principle of Moire fringes is analyzed. The fringe patterns are simulated with different deviations of two gratings which contain 49 and 50 circles （50μm periods} respectively within 5mm diameter. Such two gratings are actually manufactured and the fringes are collected. The result shows that a deviation of 2.5μm （1/20 periods} can be distinguished by eyes.