Analysis And Design Of Optical Components For Laser Marking System

Laser scanning is an important part in laser technology. High inertia laser scanning system has good linearity, high accuracy, and its frequency range can be 10~100HZ.Now it is widely used in variety of optics, machinery and power-generating equipments. Scanning with polyhedron prism can get smaller error in system in contrast of double-faced mirror Laser scanning requires the image height be linear with the entrance angle of light, which is y=f·θ, so scanning system based on F-Theta lens must be used in most Laser marking system. In the system, the scanning area mostly lies on optical performance. F-Theta lens with large working area have more minus distortion, so it can performance the liner relative of image height and entrance angle. At the same time, there can be the problem of low utilize rate of laser energy.Laser marking system is a system of optics, machinery and power-generating equipment that synthesized the technology of laser and computer. It will have more potential in development and markets of large scale. Till now, the working area of scanning lens of Laser marking system is no more than 300mm×300mm. The relatively small scanning area certainly becomes a technical obstacle.The optical design theory and method of F-Theta lens with large working area is presented concretely. The initial structure is obtained by determining the reasonable parameters through analysis of laser scanning system. By means of aberration emendation and image quality estimation, lens structure is optimized with optical design software CODE V. After the emendation of distortion and petzval blur, the F-Theta lens with 750mm in diameter is obtained. It shows the minimum width of beam less than 150μm, the visual angel achieves±30 o .This lens has a compact structure. Its focusing performance is diffraction-limited and it has high utilizing rate of energy. The system satisfies the requirements of marking on a large area.