Study Of Theory And System In 3D Near-eye Display Based On Complex Amplitude Modulation

Nowadays,the new-type display technique plays an important role in the coming technology revolution.As the main implementation model of human-computer interaction display,the near-eye display(NED)system,which has the augmented reality(AR)function,attracts more and more research interests through abroad and domestic research institutions.It can be founded many applications and great social value in military operations,industry manufacture,medical treatment,education,navigation and entertainment games,etc.The NED tends to be an indispensable instrument for people's exchange of information in the future daily life.Right now,the NED systems are mainly based on the two dimensional(2D)display panels,thus its three dimensional(3D)perception relies on the synthesis of binocular parallax principle.This kind of 3D display will cause the vergence-accommodation conflict(VAC)problem.When wearing such devices for a long time,the wearer is easily infected with uncomfortable feelings of visual fatigue,dizziness,nausea,etc.This problem restricts the application of the NED system.The using effect needs to be improved in the mass consumption domain of culture and entertainment.It also can not satisfy those highend applications of bio-medicine and military.Therefore,developing new 3D-NED system,which matches the physiological and cognitive habits of human eyes has become to the crucial research orientation of the next generation AR devices.Complex amplitude modulation(CAM)technique can manipulate the amplitude and phase of the optical wavefront,so the object is reconstructed with 3D images in arbitrary focused depths.Therefore,it is beneficial to introduce the CAM technique to the NED design.The CAM-NED system eliminates the VAC problem and improves the wearer's experience as well.Based on the CAM technique,this thesis investigated the basic theory of the 3D-NED.We proposed two 3D-NED designing methods and developed the related prototypes.The validity of the proposed methods has also been tested and the colorful 3D-NED designing idea is further proposed on the basis of the previous experimental results.This thesis mainly performs the research work in the following aspects:(1)The basic theory of the 3D-NED and CAM technique was researched.We further studied the wavefront manipulation principle and implamentation of the double amplitude holograms and double phase holograms.We also analysed the main problems of the 3D-NED system at present.(2)The 3D-NED system based on the CAM technique is proposed and studied.The CAM technique is introduced into the NED system.We designed the 3D-NED system by use of double spatial light modulators(SLMs).The related optical experimental facility is builded and the proposed method is tested its ability of continuous multiple modulation depths and dynamic 3D images reconstruction.Through testing the display property of the proposed system on multi-focus depths,we analysed its effectiveness of eliminating the VAC problem.(3)The 3D-NED system with simplified and compact structure is proposed.Combining the grating filter and frequency domain coherent superposition technology,we designed the compact 3D-NED system by use of single SLM.The cosine amplitude grating satisfying the parameter requirements was fabricated using holographic interferometric processing technology.By the aid of the structural modeling and threedimensional printing technology,the prototype of the proposed 3D-NED system was developed,the size of which is 133.8mm×40.4mm×35.4mm(with a 47.7mm length additional observation window),and the total weight of the module is 196.3g.The scene angle of view is 31.7°.When the output image resolution is 512×1024,the system refreshed the frame rate to 143 fps.An optical test system was set up to test the output performance of the continuous depth 3D image signal of the prototype,and the realtime dynamic display effect and the specific algorithm parameter indicators displayed interactively were verified.The effectiveness of the proposed method in eliminating visual fatigue was analyzed.(4)The design of the colorful 3D-NED system is proposed and investigated.Combining the CAM and time division multiplexing technique,the proposed system can fulfil 3D image display in full color.Using Zemax optical software and Matlab,the imaging quality of the proposed system was simulated and the correctness of the color CAM reconstruction was verified.At the same time,an achromatic 3D-NED prototype model was further designed in Solidworks software.The calibration of the synchronous controller was completed through optical experiments,and the optical system of timedivision-multiplexed color hologram was constructed based on the calibration parameters.The color display effect was verified.Now the prototype is under fabricating.Aiming to the VAC problem of the traditional NED system,this thesis performed a series of research work.Based on the CAM technique,we proposed three designing methods of the new-type 3D-NED systems.A compact NED prototype is further developed and tested by optical experiments,and we have achieved the designing goal of the 3D-NED,which matches the physiological and cognitive habits of human eyes.This thesis lays the foundation for the present research of the AR applications.