Research Of Wireless Power Driving And Controlling Method Of Liquid Crystal Lens

Electrically controlling liquid crystal (LC) lens has excellent electro-opticalperformances. The focal length of LC lens can be changed with the variance of thealternating signal voltage applied over the LC lens. As a relatively rapid and smart device,the LC lens can be easily fabricated into integrated device. There are two reasons for easilydriving and controlling LC lens. First, the LC lens is a special electrical loader with typicalconsume power as low as several microwatts. Second, the electrodes fabricated over the topand bottom plates of LC lens is usually made of materials with relatively large electricalconductivity such as indium tin oxide (ITO) materials. The characters mentioned above laya concrete foundation for driving and controlling LC lens through wireless power drivingand controlling mode.The wireless power transmission is a novel driving and controlling method for LC lens.Based on the conditions of the weak electromagnetic induction coupling and resonancebetween hollow windings, the wireless power transmission circuit is able to drive LC lensthrough penetrating air of electromagnetic waves generated. The hollow windings can notonly be made into the stacking structures, but also the planar structures with small size,light weight, and simple layout, which is very important for developing the integratedstructure between the LC lenses and the driving and controlling devices. This dissertationdemonstrates the designing method of the inductance of stacking coils and the mutualinductance between planar coils with different shape, and the technological flow of thecoils fabricated, and several key parameters, and the calculation method of the induction ofcoils. The developed coil structures can meet the requirements of the LC lens drived bywireless power transmission mode.The developed analysis method of wireless power transmission circuit is mainlyinclude:(1) the circuits can be simplified as a circuit system model including input signal,output signal, and the transmission function;(2) the relationship between the input signalpulse width and the frequency and the amplitude of output signal voltage are established,respectively, based on Fourier series expansion theory of periodic signal and circuit theoryof Lipase transform domain analysis. After establishing the circuit model, the actual circuit is constructed according to the parameter arrangement generated by the model. Thewireless power transmission circuit has the several advantages such as simple structure,smart driving and controlling mode, retentively high driving efficiency, and low cost. Theexperiments and theoretical analysis demonstrate that the driving voltage of the LC lens canbe modulated continuously from~0Vrmsto30Vr ms, through only changing several parametersof input signal such as the duty cycle of the signal. The testments show that clear focusingpatterns over the focal plane of LC lens can be formed through driving LC lens by wirelesspower transmission mode developed.