Research, Design And Realization Of Optical System And Mechanical System Of Large Format Scanner

Scanner is an integrative high-tech product of optics, electronics and mechanicsand is used to convert the traditional analog image into digital image. Nowadays A4format scanner is widely used in office and the requirement of scanner in someengineering fields increases. Large format scanner can be used in many fields such asmechanics, architecture, water conservancy, reconnaissance, city planning, publishand so on. Generally they are often used to scan and store the blueprints, posters andsome costly files. There are many kinds of large format scanner products in marketnowadays but no one that designed by Chinese company or institution. So it is atough project to design and produce large format scanner.In the scanner system, the optic-electronic system is the core of scanner. It is incharge of formation image of the material on the photosensitive surface of CCD(Charge Coupled Device) and converts the optic signal into electronic signal. So thequality of output image is directly affected by the performance of theoptic-electronic system. And, because of the obvious difference between largeformat scanner and A4 format scanner which are large format, large size and weight,we need spelling several optic units to scan the whole format (usually it is A0format).According to the design requirements, the composition of system and the wholestructure, including the control system and optical system, are analyzed, and thesensors, lens and lamps are chosen. According to the requirements of large formatscanner size, several plans of reflection optic system are designed and finally asatisfying plan is chosen after comparing and improving. In the end the chosen planis simulated by using AutoCAD software to produce 3D model.An optic examination table was set up to test the chosen plan. In experiment thesystem collects many images by using our scan software. The scan modes of unit areimmovable and movable. The result of examination shows that the chosen design isaccorded with the design requirements. In the end of this paper, mechanical system isdiscussed.Large format scanner optic system was successfully designed and manufactured,and finally applied in the product of SmartLF of Tsinghua THUNIS Company.