80-caliber Bird-watching ED Lens Optical System Design

As the modern people's understanding of the ecological environment, bird-watching activities have become increasingly popular, making it industry economic benefits. At present we can see mainstream bird-watching telescope's caliber below 100 millimeters.The subject of 80-caliber bird-watching telescope ED lens optical system design,the objective lens diameter D=80mm, it requests adjust the secondary specture and the color spherical aberration, therefore the objective lens use three separation structure, to adjust the image quality and apochromatism. After design, it meets the image quality requirements of the object lens:On objective lens axis transfer function MTF (1201ps/mm)≥0.2,0.7 field of MTF (601ps/mm)≥0.2. Because the demand of eyepiece field of view is too large,2ω= 65°,focal distance f=12mm,distance of exit pupil is longer than length, so the new Huygens'eyepiece structure is used.Using this structure design,it meets the quality requirements:On eye lens axis transfer function MTF (1201ps/mm)≥0.2,eye lens relative distortion≤10%.The objective in this design process, the optical design process is divided into four stages:determine optical system performance, choose the appropriate initial structure, optimization, image quality evaluation. The design uses ZEMAX software, ZEMAX software through the various aberration curve analysis can optimize systems that meet design requirements.The purpose of this thesis is to design a high-quality imaging optical system,it has reasonable structure, large diameter, high resolution, good color reproduction, comfortable observing and easy to carry, it suitable for mass consumption of the bird-watching telescope.