出一种适用于增强现实的视网膜显示技术, 利用一个相位型空间光调制器结合计算机全息图算法, 实现了直接在视网膜上进行全息重建。首次从理论出发, 给出了相位型空间光调制器输入相位与眼球前平面光场的计算关系, 讨论并比较了基于GS的全息图计算方法和基于双相位编码的复振幅调制全息图计算方法的特点, 采用复振幅调制, 全息重建中的散斑噪声得到抑制。仿真和实验结果验证了应用于视网膜全息成像的计算机全息图算法的有效性。实验证明, 该方法能够利用一个纯相位空间光调制器在眼球里进行多平面的无散斑全息重建, 同时在视网膜附近重建振幅信息, 使得眼睛聚焦在某个平面时, 该平面的图像能够恰好投影在视网膜上。整个过程模拟了自然场景中人眼调焦和观察的过程, 不同于双目视差的三维显示方法, 文章提出的视网膜显示技术是一种真三维全息重建, 不存在视觉辐辏调节冲突。

A single phase-only spatial light modulator and a double phase method were used to directly modulate the light at multiple planes inside the eye. The numerical relationship of light distribution between SLM plane and the plane in front of the cornea was firstly given, and then the difference between holographic reconstruction by traditional GS algorithm and complex modulation based on double phase method were discussed. Due to the complex modulation, the speckle noise was reduced. Both computer simulation and optical experiment have been conducted to verify the effectiveness of the proposed electro-holographic retina display method. The method could employ a phase-only SLM to implement multi-plane speckleless holographic reconstruction inside the eye. By changing the focal length of the eye, images at different depth planes were sharply projected onto the retina, with which the accommodation of natural vision was mimicked. Different from three-dimensional(3D) display method based on binocular parallax, the proposed method is a true 3D holographic reconstruction method, which could solve the accommodation and convergence conflict problem for augmented display.