Optical Design of the N.A.1.1 Infinite Conjugate Microscopic Objective

In order to solve the serious problem of ordinary biological microscopic objective lenses including field distortion, chromatic aberration and low resolving power, a high-resolution infinite conjugate microscopic objective with three fourth-order Zernike polynomial surfaces has been presented in this paper. The numerical aperture of microscopic system is 1.1 with 2.6mm focal length, which can be equipped with most field lens. The design and analysis results show that the par focal distance of the objective lens is 45mm, and the incidence angle and refraction angle of the optical surface of the lens are less than 60°, which meets the international standard of the microscopic objective lens. The optical modulate transfer function (MTF) curve is close to the theoretical diffraction limit and the RMS wavefront error of the high-performance microscopic objective satisfied Marechal criterion. In addition, the tolerance analysis results show that the system can be processed based on the existing machining methods, despite the wavefront aberration RMS will deteriorate to 0.25λ. The whole system can be used in genetic testing research and mirror test, which is expected to promote the development of medical testing and industrial test and become one of new generation of diagnostic tools.