Design Of Plan Apochromatic Objective Lens With Wide Spectrum And Large Numerical Aperture

Because the near-infrared light has the advantages of good organizational penetration and minimum biological sample damage,the near infrared fluorescein has been applied to detect mutations in cancer cells in recent years.However,the existing objective can't cover visible light and near-infrared light at the same time,the objective should be changed according to the fluorescein.So the microscope objectives with wider spectrum covering visible light and near-infrared light become a hotspot.In the light of the limitations that the fluorescence induced by mutant gene has weak intension and board spectral region,the existing microscope objectives are not qualified for detection,I will design a 40× fluorescence microscopy objective with the spectral range of 450?800 nm and 0.95 numerical aperture.The objective used"++-" structure,because the correction of aberration causing by wide spectrum and high numerical aperture is difficult,the objective must include a set number of lens and the align process will be difficult,the front group,taking more than 90%focal power,is set as the sensitive component and is useful for adjusting in the align process;the middle group is the weak focal component,which is used to correct the secondary spectrum causing by the large numerical aperture,so that the manufacturing difficulty of the apochromatic elements is reduced significantly.The posterior group is the negative component,which is useful for flatting the image field and increasing the working distance of the objective.The results show that the image quality almost reaches the diffraction limit,meeting the surveilling requirements of weak fluorescence signal in cancer cells.Besides,I chose the elements which can adjusting the spherical aberration and coma of the objective.The tolerance analysis is carried out using RMS Spot Radius and Wavefront RMS value as the standard,then the system tolerances meeting the actual machining level are given and the related drawings are drawn.Finally,the assembly and inspection of ten groups of objects are completed.