Research On Three-dimensional Micro Imaging System Based On Liquid Zoom Lens

Microscopic systems can be used to observe tiny objects and are widely used in biological research.At present,the observation means of two-dimensional morphology of biological structure have been very mature,and the observation means of three-dimensional morphology of biological structure are still developing.the system uses the liquid zoom lens as a zoom element and adds it to the microscopic imaging system.by changing the position of the imaging object surface through the zoom of the liquid zoom lens,the moving sample can be avoided,and the performance of the imaging system can be improved to a certain extent.Because the research of three-dimensional microscopic imaging system based on liquid zoom lens has important theoretical significance and practical value in the field of biological detection,it is necessary to study the three-dimensional imaging system based on liquid zoom lens.Main work of this thesis:1.Designed a liquid tunable microscopic imaging system.The illumination system part adopts two kinds of illumination modes of light sheet fluorescence and transmission type to meet the observation needs of different samples;the image acquisition system part adopts the double telecentric optical path.The dual telecentric optical path can ensure that the system magnification remains unchanged during zooming.The liquid tunable lens is placed at the diaphragm position of the bi-telecentric optical path to ensure that the position of the object plane is linearly related to the power of the liquid lens.The designed imaging was simulated using zemax optical simulation software,and system MTF curves with different apertures and different magnifications were obtained.During zooming,the scanning range is linearly related to the change range of the power of the liquid tunable lens,the system magnification is basically unchanged,and the MTF curve is basically unchanged.2.Build a three-dimensional microscopic imaging system based on liquid tunable lens,and verify the system characteristics,including the system object plane position,depth of field,magnification and resolution.For the measurement of object plane and depth of field,a method to judge the object plane and depth of field according to the gradient function value of the image is proposed.Variance function is used to determine the object plane change,and Tenengrad gradient function is used to determine the depth of field range.The system magnification is 7 times,which is in good agreement with the theoretical value of 7 times;the system resolution is 144.0 lp / mm,which is about 7 μm,and the gap between the theoretical value and 5 μm is small.During liquid lens zooming,the system magnification and resolution remain basically unchanged.3.The fluorescent microspheres were imaged using the system under fluorescent light illumination,and the system feasibility under fluorescent light illumination was verified.The semi-conical three-dimensional printed samples were observed under the transmissive illumination mode.Ten images were collected within a range of 3mm.The three-dimensional images of the semi-circular platform were obtained after fusing the images,which was consistent with the original semi-conical features.The work in this thesis has guiding significance for the field of biological detection,and may be used to image the three-dimensional topography of living biological samples.