Study On Liquid Zoom Lens Driven By Ultrasonic Vibration

Normal lens requires mechanicalmovementand it has the problem of high cost and short life.Meanwhile,theliquid lens has been applied in many aspects because of advantages of simple structure and does not require mechanical movement.Liquid lens is one of the new zoom lenses.In recent years,liquid lens has developed rapidly.At present,there are many researches on liquid zoom lenses,such as electric wetting,liquid crystal,hydraulic and ultrasonic drive.The ultrasonic vibration zoom lens has many advantages,such as fast response speed and wide range of zoom.In this paper,the mechanism of ultrasonic vibration driven liquid zoom lens is studied.It is mainly includes the following three aspects:Firstly,this paper proposed a novel structure of ultrasonic vibration driven zoom lens,which is composed of piezoelectric ceramic,transparent film and liquid.The theoretical model of the lens is set up.From the acoustic theory,the pressure produced by the lens in the radial and longitudinal vibration of the piezoelectric ceramic is analyzed.The influence of pressure distribution on the surface curvature radius of liquid is studied,and the mechanism of this zoom lens is analyzed theoretically.The research shows that the mechanism of the change of the radius of curvature of the liquid surface is different.When the piezoelectric ceramic radial vibration is vibrate,the pressure distribution of the proposed lens is small in the centerand large in the edgeand the longitudinal vibration of the piezoelectric ceramic produces a small central edge pressure on the liquid surface.Secondly,ANSYS finite element method is used to simulate the vibration modes of ring piezoelectric ceramics at different resonance frequency points,which is verified by experiments.A pressure sensor is used to measure the pressure on the liquid air interface,which is compared with the theoretical analysis,thus verifying the accuracy of the theory to reveal the zoom mechanism of the lens.The distribution of liquid surface displacement is measured under different driving voltages.Experimental results show that the focal length of liquid lens can be changed by the input voltage.Finally,the experimental optical path is built,and the focal length of the lens under different two modes of vibration is calculated by means of image processing.Meanwhile,a novel method of elimination aberration is proposed through the research of the relationship between the result of lens imaging and the aberration of the zoom lens.The results show that the liquid lens can change the concave and convex type of the lens by using different resonant frequency points to change the type of the concave and convex of the lens,and change the focal length of the lens by changing the size of the input voltage.The new zoom lens has many advantages,such as wide zoom range and fast response speed.The mechanism and conclusion of the research are of great significance for the further optimization of the lens under the action of ultrasound.