Research On Fabrication System Of Aspherical Glue Microlens Based On Machine Visual Inspection

The technology of micro-organism fluorescence detection for airspace applications is required to meet the standards of automatic detection,micro structure and functional integration.In general,the system uses the micro photoelectric detection devices for fluorescence detection.Because the fluorescence signals are weak and photoelectric sensors sampling value changes are tiny,using specific surface shape of aspherical optical microlens before the photoelectric conversion to increase the amount of photon acquisition,which makes the fluorescence detection system more sensitive response.In this particular application of aspherical microlens,we present a new fabrication system of aspherical glue microlens and real-time fitting matching method,aiming at using this system and method to produce the required microlenses directly,according to the given aspherical microlens equation.In this paper,the fabrication system of aspherical glue microlens based on machine visual inspection is designed according to the regulation of droplet surface shape by high-voltage electric field.This paper introduces the overall design of the system,which consists of three parts: surface shape control and movement unit,UV curing unit and image acquisition and processing unit.We complete the structure design of the experimental platform,as well as the construction of hardware and software.The surface shape control and movement unit provides a voltage-controlled electric field and uses the electric field to manipulate the surface shape of the optical glue droplet.The stepper motor drives the adjustment of the displacement between the electrodes and the position adjustment of the UV LED curing light source.The UV curing unit enables the light source to turn on and off,adjusts the output power,and implements the glue droplet curing function.The image acquisition and processing unit consists of a zoom lens and a CMOS camera.After capturing,denoising the image by filtering and binarization,a dynamic droplet profile can be obtained and stored as a Freeman chain code.In this paper,fabrication system of aspherical glue microlens was used for experiments.The lenses are made of NOA61 type UV-curable adhesive,which is more sensitive to ultraviolet light of 350-380 nm wavelength.We investigate the effects of electric field voltage and electrode shape on the surface morphology of glue droplet.Based on the mastery of the preparation process,the fabrication experiments of elliptical lens,parabolic lens and hyperbolic lens are developed.Based on contour fitting evaluation algorithm of Freeman code,the lens contour with higher fitting degree is obtained,and the glue droplet is cured under the condition of the best fitting degree.Finally,elliptical microlens,parabolic microlens and hyperbolic microlens are fabricated.