用于智能显示的相位型计算全息图的设计

介绍了一种基于相息图原理的用于智能显示的纯相位型计算全息图的设计方法,并在此基础上,以雪花图形和分划板图形为例,完成了全息元件实验样件的制作及全息再现实验,这种实时再现的图像可以用于智能显示。在已知记录介质折射率的情况下,通过控制纯相位型计算全息图记录介质表面微结构的宽度和高度来调制光波,得到所需图像。采用逐步迭代的傅里叶变换算法来获取纯相位型计算全息图的相位结构,为了降低相位型计算全息图的制作难度,提出量化数学模型,并对所设计的相位结构进行量化处理,给出了纯相位型计算全息图的4台阶浮雕型相位结构。全息元件的尺寸设定为6mm×6mm,工作波长为650nm,衍射结构的最小特征尺寸为8μm。理论计算和模拟再现像的结果表明,在未考虑加工误差的条件下,所提供的这种用于智能显示的纯相位型计算全息图的设计方法是可行的。此方法可推广用于其它任意特定图案的纯相位型计算全息图的设计,也可用于设计具有光束整形功能的衍射光学元件,如离轴照明的光束的整形匀光器件等。用于智能显示时,用平行光照射制作的实验样件,只得到的单一的衍射图像,不存在其他衍射级次的图像,在考虑采用台阶量化结构和存在加工误差的情况下,衍射效率仍然很高。若改变设计的全息图相位的正负,并用平行光以特定的角度照射制作此相位型计算全息图,可用于全息瞄准。

Design of phase type computer-generated-hologram for intelligent display

The design method of the pure-phase type computer-generated-hologram for intelligent display based on the principle of the kinoform has been introduced. On this basis, taking snowflake pattern and reticle pattern as examples, experimental samples of holography elements was developed, and holographic reconstruction is completed, real-time reconstruction images can be used for intelligent display. Method:The reconstruction images could be obtained by controlling the height and width of micro-structures on the surface of recording medium material with a certain refractive index. The iterative Fourier transform algorithm has been used to calculate the phase structure of the pure-phase type computer-generated-hologram. At the same time, the quantitative mathematical model has been given, and 4 steps relief structure have been obtained. The sizes of the pure-phase type computer-generated-hologram has been set to be 6 mm×6 mm, the working wavelength is 650 nm, the minimum feature size of the diffractive structures is 8 μm. The theoretical calculation result and the reconstruction simulation result show that the design method of the pure-phase type computer-generated-hologram for intelligent display is feasible in the case of un-considering fabrication errors. This method can also be used to design the pure-phase type computer-generated-hologram of other specific patterns. It can also be used to design diffractive optical elements for beam shaping, such as the optical beam shaping and optical beam homogenizer of the off-axis illumination. The pure-phase computer-generated-hologram is illuminated by a plane wave for intelligent displays, the high diffraction efficiency could be obtained because a single diffraction image could be reconstructed without other diffraction images. The positive and negative of phase of the hologram is changed in this design, the hologram is illuminated by a plane wave at a specific angle, which can be used for holographic sight