Liu Yue, Cheng Dewen, Yang Tong, Chen Hailong, Gu Luo, Ni Dongwei, Wang Yongtian
Opt Express. 2022 Jan 17;30(2):825-845. doi: 10.1364/OE.443682.
Multifocal imaging has been a challenging and rewarding research focus in the field of imaging optics. In this paper, an ultra-thin multifocal integral LED-projector based on aspherical microlens array (MLA) is presented. A two-layer aspherical sub-lens with NA = 0.3 is proposed as a sub-channel projector and the optimization design ensures high optical integration precision and improves optical efficiency. To avoid the tailoring loss of the projected images between multi-plane projections, the central-projection constraints between size and projection distance for the multifocal projection are defined. The depth of focus (DOF) analysis for MLA and sub-lens is also introduced to proof the sufficiency of realizing multifocal projection. Combined with the radial basis function image warping method, multifocal sub-image arrays were acquired, and three types of multifocal integral projection were realized, breaking through the traditional limitations of the single-focal DOF. A prototype with thickness of less than 4 mm is developed. Substantial simulations and experiments are conducted to verify the effectiveness of the method and the design.
多焦点成像一直是成像光学领域中一个具有挑战性但又成果丰硕的研究重点。本文提出了一种基于非球面微透镜阵列（MLA）的超薄多焦点积分式LED投影仪。提出了一种数值孔径（NA）为0.3的双层非球面子透镜作为子通道投影仪，优化设计确保了高光学集成精度并提高了光学效率。为避免多平面投影之间投影图像的裁剪损失，定义了多焦点投影在尺寸和投影距离之间的中心投影约束。还引入了对MLA和子透镜的景深（DOF）分析，以证明实现多焦点投影的充分性。结合径向基函数图像变形方法，获取了多焦点子图像阵列，实现了三种类型的多焦点积分投影，突破了单焦点DOF的传统限制。开发了一个厚度小于4毫米的原型。进行了大量的模拟和实验，以验证该方法和设计的有效性。
