Optical System Design Of Apochromatic Collimator With 350mm Aperture

The collimator is an important equipment for photoelectric equipment calibration and optical system calibration,and it is also an important member of optical measurement instrument.It is mainly used to generate parallel light and simulate an infinite target.According to the requirements of the project,in order to test the stability accuracy of the aiming line and the stabilizer of the tank electric testing equipment under certain working conditions,it is necessary to provide the simulated target source by collimator.As an army photoelectric standard test equipment,its optical system parameters are:50mm aperture,400mm focal length,full field of view was 2-4°.Due to the limited testing place and environmental conditions,there are few special equipment for provided the infinite targets when calibrated the artillery sight and vehicle sight at the same time.So it is necessary to developed high precision optical system for special needs to provide infinite simulated targets.According to the design requirements of this project,a transmission achromatic collimator with 350mm aperture,1.5-3.5m focal length,full field of view greater than 3°,and working band was 400-700nm needs to be designed.In order to solve this problem,design and study from the following two aspects:(1)Combined with the structure characteristics of Gaussian optical system,the Gaussian lens is selected as the initial structure of optical system,and seven kinds of primary aberrations are corrected firstly by using the operands reasonably.Combined with the aberrations theory of the large aperture optical system and the characteristics of the diffractive lens,the standard plane of the lens is gradually replaced by the binary diffractive plane,the achromatic optical system of hybrid refractive-diffractive was designed,and full field of view is 5.6~°,the optical system meet the design requirements;(2)In order to overcome the difficulty of aspheric processing,cook separate lens was used as the initial structure of optical system,to design an achromatic optical system with spherical lens.According to the theory of advanced aberration,the paraxial lens method is used to increase lens number of optical system,distribute the optical power of lens reasonably,correct the advanced aberration and chromatic aberration.Finally,without introduced the aspheric surface,the optical system of achromatic collimator was designed,and the full field of view is 3.5~°.These two optical systems are close to the diffraction limit,the RMS value of wave aberration is better than?/20,and the different wavelengths of color light intersect at 0.707band,which realizes the achromatic.Compared with the two optical systems,it is found that the astringency rate of aberration correction of the optical system with introduced diffractive surface is fast,but it is not easy to processed the glued lens of large aperture system,so the performance of the optical system with separated spherical is better.Finally,the effect of temperature and pressure on the image quality of optical system is analyzed,and the effective compensation measures of temperature and pressure are proposed.The tolerance analysis of optical system is carried out according to the requirements of machining.Two methods for measuring the parallelism of the outgoing parallel light of the collimator are proposed.