| Near-infrared microscopy imaging technology makes full use of the band characteristics of near-infrared spectroscopy and has a wide range of applications in the fields of chemistry,biology,materials science,mineralogy,and food science.Among them,the near-infrared band greater than 1200 nm has good penetrability to silicon-based materials.The project team applied it to the non-destructive measurement of the characteristic parameters of silicon-based semiconductor devices and achieved remarkable results.The optical components of the nearinfrared microscopic imaging system are mainly composed of three core parts: a microscopic objective lens,an imaging tube lens and an illumination system.At present,most of the reflective microscope objectives in this waveband on the market have a central obstruction and poor image quality.Therefore,there is an urgent need to study near-infrared transmissive microscope objectives.According to the development needs of the near-infrared microscopic imaging system,this paper carries out the research on the design method of the near-infrared microscopic objective lens,the illumination system and the imaging tube lens,and designs and assembles a near-infrared Fizeau interferometer with a working wavelength of 1310 nm to meet the requirements of the lens check requirements for wave aberration.First,the design of a 20×near-infrared microscope objective lens with a spectral range of 1250～1350 nm,a numerical aperture of 0.5,an object field of view of ±0.35 mm,and a parfocal distance of 60 mm was completed;then the Koehler illumination system was designed as a microscope objective.An illumination pupil of Φ11.6mm is provided,which meets the uniform illumination requirements of the 20× objective field of view;the design of an imaging tube lens with a focal length of 200 mm is completed.In order to solve the wave aberration detection requirements of the nearinfrared lens,a single-detector small-aperture near-infrared Fizeau interferometer was designed.By rationally arranging the beam splitting and merging of the interferometric imaging optical path and the alignment optical imaging optical path,the interferometric and the alignment imaging path share the same near-infrared detector;through the optimization of the shelf products and the optical path design,the optical path of the interferometer is not customized.The optical component effectively realizes the cost control of the near-infrared interferometer;through the auxiliary installation and adjustment of the near-infrared test card,a phase-shifting near-infrared Fizeau interferometer with an operating wavelength of 1310 nm and an effective aperture of 15 mm has been successfully developed.Using a near-infrared Fizeau interferometer with a working wavelength of 1310 nm to detect the designed and assembled20× microscopic objective,the on-axis field of view wave aberration is better than the RMS value "0.008λ",and the edge field of view is better than the RMS value "0.023λ.".The image quality is good. |
