Optical design for large depth of field

Optical system with large depth of field and large field of view has been designed. To enforce optical system with focal length of 6 mm to imaging the object with object length of 200mmm-1200mm, accord to the equation of depth of field, in case of the CCD sensor with pixel of 5.5umx 5.5um square area, the entrance pupil diameter to ideal imaging will be 0.423mm. To enlarge the modulation transfer function (MTF) at spatial frequency of 90 lp/mm, the entrance pupil diameter is enlarged to 1mm.After design and optimization, with field of view of 80°, within object length of 200mm - 1200mm, the optical system can imaging well, the modulation transfer function (MTF) at spatial frequency of 90lp/mm is larger than 0.1, the distortion of full field of viewed is less than 3%.The optical system can be widely used in machine vision, surveillance cameras, etc.