| 3D(Three dimensional)display can make observer enjoy the immersive viewing experience.It's become the ture trend which the display technology would be develop.Holography is the trend of ture 3D display because of its technology that it can restore the complete visual information of objects.Traditional holographic display technology record the 3D display information on the holographic dry plate.While the the image can be perfectly present in space,it is unable to realize real-time and dynamic show.Loading computer generated holograms on SLM(spatial light modulator),can realize 3D visual effect.At the same time,modulation of spatial light modulator to the incident light can be real-time and dynamic.There are many different kinds of spatial light modulator and one of them is based on liquid crystal silicon technology of silicon-based liquid crystal spatial light modulator(liquid crystal on silicon,LCOS).It has advantage of high resolution,high integration of workpiece,high pixel filling rate and high speed of refresh.Recently,it is widely used.This paper includes the following aspects of research:(1)The paper study the development of SLM devices and the challenges of using LCOS to realize dynamic 3D display are investigated.Through the comprehending of the nature of liquid crystal and analysis of LCOS holographic reconstruction process,finding out the cause of LCOS could not be applied to the dynamic holographic display.(2)Based on free energy distribution theory of liquid crystal,we can pushed out the computational formula of liquid crystal molecules' configuration of molecule direction,and using iterative algorithm to calculate the liquid crystal molecules' configuration of molecule direction which are in the electrical fields.With the modulation law of liquid crystal to the light wave,it can accurately calculate the depth of liquid crystal on silicon modulate the phase of light.(3)We deeply study and analysis the concept of fringing field effect.And based on COMSOL software,we simulate the distribution of adjacent pixels electric field which is in the LCOS box,at the edge of the working voltage.The paper depicts the electric field equipotential surface curve in the LCOS boxUnder the condition of the electric field,it simulated the distribution of the liquid crystal molecules in a LCOS.It analyze the influence of the fringe field on the phase modulation,in the liquid crystal optical system.In order to solve the problem of fringe field effect in LCOS system,we point out a new type of electrode structure,vertical electrode structure.we analyze the distribution of the fringe field between adjacent pixels in three model.It is include the traditional electrode structure model,two side interdigital electrode model and vertical electrode model.Morever,we insist the advantage and weakness in eliminating the fringe field effect among three kinds of electrode model.(4)With COMSOL software,we simulate electric field distributions of three pixel electrode model in LCOS.Reading every voltage of the liquid crystal box and draw a curve about them.Through the simulation results and the curve comparison of the three pixel electrode model,we finally pointed out that the vertical electrode structure can suppress the fringring field effect,most effectively.It offer a new solution to using LCOS to display tiny pixels.Key words:LCOS,holographic imaging,edge effect,phase modulation,viewing Angle. |
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