Chen Haiwei, Weng Yishi, Xu Daming, Tabiryan Nelson V, Wu Shin-Tson
Opt Express. 2016 Apr 4;24(7):7287-98. doi: 10.1364/OE.24.007287.
We proposed a switchable beam steering device with cycloidal diffractive waveplate (CDW) for eye tracking in a virtual reality (VR) or augmented reality (AR) display system. Such a CDW diffracts the incident circularly polarized light to the first order with over 95% efficiency. To convert the input linearly polarized light to right-handed or left-handed circular polarization, we developed a broadband polarization switch consisting of a twisted nematic liquid crystal cell and an achromatic quarter-wave retardation film. By cascading 2-3 CDWs together, multiple diffraction angles can be achieved. To suppress the color dispersion, we proposed two approaches to obtain the same diffraction angle for red, green, and blue LEDs-based full color displays. Our device exhibits several advantages, such as high diffraction efficiency, fast response time, low power consumption, and low cost. It holds promise for the emerging VR/AR displays.
我们提出了一种带有摆线衍射波片（CDW）的可切换光束转向装置，用于虚拟现实（VR）或增强现实（AR）显示系统中的眼动追踪。这种CDW能以超过95%的效率将入射圆偏振光衍射到一阶。为了将输入的线偏振光转换为右旋或左旋圆偏振光，我们开发了一种由扭曲向列液晶盒和消色差四分之一波延迟膜组成的宽带偏振开关。通过将2 - 3个CDW级联在一起，可以实现多个衍射角。为了抑制色散，我们提出了两种方法，以在基于红、绿、蓝发光二极管的全彩显示器中获得相同的衍射角。我们的装置具有几个优点，如高衍射效率、快速响应时间、低功耗和低成本。它在新兴的VR/AR显示器领域具有广阔前景。
