Opt Express. 2022 Sep 26;30(20):36632-36643. doi: 10.1364/OE.473125.
We analyze an image quality of a holographic lens (HL) in order to implement compact near-eye displays using a flat-panel-type micro-display panel. The proposed method utilizes a non-converging signal wave in a fabrication process of the HL, so that it provides affordable eye-box size with minimizing the aberration due to rays in the off-Bragg condition. For analyzing and optimizing the HL based on the non-converging signal wave, we introduce a comprehensive analysis model for an assessment of the image quality in the HL. The analysis model, inspired from the conventional lens design strategy for near-eye displays, evaluates the focal spot quality for incident rays forming each pixel with considering the on- and off-Bragg diffraction. The theoretical analysis is validated by simulation results using a volume hologram model in Zemax OpticStudio. As experimental verifications, we realize a prototype system using photopolymer-based HLs in a green color with the high transmittance of 89.3%. The image quality of the HLs is analyzed, which coincides well with the proposed analysis and assessment metric. By building a compact experimental setup employing the HL and a micro-organic light emitting diode display, we present see-through images with 8.0 mm of eye-box with reduced aberrations.
我们分析了全息透镜 (HL) 的像质，以便使用平板型微显示面板实现紧凑的近眼显示器。所提出的方法在 HL 的制造过程中利用了非会聚信号波，从而通过最小化由于离布拉格条件的光线引起的像差来提供可承受的眼盒尺寸。为了基于非会聚信号波分析和优化 HL，我们引入了一个综合分析模型，用于评估 HL 中的像质。该分析模型受到用于近眼显示器的传统透镜设计策略的启发，通过考虑在布拉格和离布拉格衍射，评估形成每个像素的入射光线的焦斑质量。通过在 Zemax OpticStudio 中使用体全息图模型进行模拟，验证了理论分析的有效性。作为实验验证，我们使用高透光率为 89.3%的基于光聚合物的 HL 实现了一个原型系统，该系统具有绿色颜色。分析了 HL 的像质，其与提出的分析和评估指标吻合良好。通过构建采用 HL 和微有机发光二极管显示器的紧凑实验装置，我们展示了具有 8.0mm 眼盒的透视图像，并且像差减小。
