Research On The Structural Of Two-dimensional Zero-reference Gratings

With the development of micro-electronics industry and nanometer-machining technology, the demand for positioning is more and more increasing. Most of flat roofs with high precise choose grating as their measurement system. In order to improve the grating's accuracy, it needs changeless position to correct errors. Many scholars study on the methods about zero positioning of precise gratings at all the times.Recently with the development of two-dimensional gratings, two-dimensional zero-reference gratings are studied which produce changeless zero. For demand of flat roofs with big range , the article proposes a new kind of two-dimensional coded zero-reference gratings, which obtains the zero-reference signal from the specially codes in two-dimensional direction to fleetly achieve absolute measurement. Compared to usual orientation sets, the two-dimensional zero-reference gratings have higher accuracy and better stabilization, which have abroad application room.The research is based on the project sponsored by the National Natural Science Foundation of China (NSFC). To be summarized, the main contents and the results of the research are as below:(1)Studied the characteristic of light flux of the zero-reference gratings with random codes, and optimized codes of the zero-reference gratings by computer simulation.(2)Confirmed the structure of the two-dimensional zero-reference gratings and designed the experiment fittings for the system.(3)Finished the adjustment of the experiment fittings, at the same time progressed the performance experiment of the system.(4) Assessed and analyzed the result of the experiment.