Application Research Of Micro-lens Array In Scanning Optical System

The large field of view(FOV)and high resolution(HR)are always the inherent contradictions of the imaging optical system,and the scanning optical system is a common method to solve this contradiction.In order to seek a scanning method with small volume,high rate and large angle,the application of micro-lens array in the scanning optical system is researched in this paper.And two micro-lens array systems for scanning imaging are designed.1 A micro-lens array system for transceiver continuous scanning(1)Design of the micro-lens arrayTaking the Kepler telescope structure with a field lens as the prototype,and taking the receiving optical path as the design direction,we design a two-piece micro-lens array with ±1.06° instantaneous FOV and ±8° scanning FOV.The apertures of the micro-elements in incident and emitting port keep consistent in order to realize transceiver sharing and avoid the loss and crosstalk of light energy.(2)Analysis of the micro-lens array systemAfter splicing the micro-lens array and the receiving objective,the stray light and tolerance analysis are completed.It is verified that the crosstalk between microelements is weak and the result meets the design requirements.And we have specified the parameters that need special attention when machining through tolerance analysis.2 A micro-lens array system for three FOV switched(1)Layout arrangement of system structureAccording to the design purpose of three FOV switched imaging and the characteristic of the mid-infrared imaging optical system,the structure layout is carried out.We have confirmed to use the wedge to cut apart the FOV,apply the former objective to transform the system field information into the aperture angle information,employ micro-lens array to select switch three segments of FOV,and use the rear objective to image the selected FOV on the refrigeration detector.(2)Design of each part of system structureBased on the relationship between the optical system aperture and the FOV,the specific parameters of the structure of each part of the system are calculated.We design the wedge group,the front lens,the micro-lens array and the rear objective lens in turn.And the complete optical system with a total length of 452.8mm switches among ±20° in Y direction.(3)Analysis of micro-lens array systemThe micro-lens array system is analyzed by the theories of stray light,cold reflection and tolerance analysis.It is verified that no crosstalk occurs among the three segments of FOV when switching the field of view.The surface with strong cold reflection effect is analyzed,which can seek out ways to restrain the cold reflection effect of optical system.We have made sure the optical parts with more sensitive tolerance to determine the possibility of processing the system.