Study On The Positioning Technology Of Long Distance And Submicrometer Accuracy Laser Direct Writing Device

The Binary Optics Elements(BOE) Laser Direct Writing device is the key device which is used to fabricate Binary Optics Elements. The motion control system of the device is a precision four-axis trace control system. Two-Dimension or three-dimension motion can be realized by the system to produce all kinds of BOE. Because of long distance and high accuracy, making the device will include photolithograph, precision mechanic, 3-dimension precision positioning, focusing, leveling and figure inputting technologies.Base on the most advanced LDWD in the word and fabrication of BOE, the positioning technology of control system of BOE-LDWD is researched into deeply . So this paper consists of following sections:Section 1. According to the actual working situation and the requirement of BOE laser writing device, a complete, compact, real-time, and economical motion control system is designed. The working principle and realized method of each part of the device is presented.Section 2. The characteristics of PZT are analyzed. The control method of PZT isn't suitable for LDWD. A new control circuit is designed, which can satisfy the accuracy and bandwidth of the device.Section 3. Two-stage positioning method is used to realize fast-precision positioning. The high-frequency characteristic of PZT is exploited to make emotion of the device smoother. At the means time, the change ofposition produced by the force releasing of mechanic and the interval of mechanic is smoothed away. The positioning accuracy in 2mm of axes reach.1um. The positioning accuracy in 200mm of axes reach ?.2um. The positioning accuracy in 200mm X 200mm X 40mm of device reach ?.29um.This system has passed a measure of national measure bureau.Section 4. The leveling couple model of LDWD is constructed. The etching head be used to measure the leveling error signal. Uncouple control method is used to realize leveling uncouple. At mean time, the radius of beam be compensated to improve the accuracy of positioning of the etching point.