Li Guoqiang, Mathine David L, Valley Pouria, Ayräs Pekka, Haddock Joshua N, Giridhar M S, Williby Gregory, Schwiegerling Jim, Meredith Gerald R, Kippelen Bernard, Honkanen Seppo, Peyghambarian Nasser
College of Optical Sciences, University of Arizona, Tucson, AZ 85721, USA.
Proc Natl Acad Sci U S A. 2006 Apr 18;103(16):6100-4. doi: 10.1073/pnas.0600850103. Epub 2006 Apr 5.
Presbyopia is an age-related loss of accommodation of the human eye that manifests itself as inability to shift focus from distant to near objects. Assuming no refractive error, presbyopes have clear vision of distant objects; they require reading glasses for viewing near objects. Area-divided bifocal lenses are one example of a treatment for this problem. However, the field of view is limited in such eyeglasses, requiring the user to gaze down to accomplish near-vision tasks and in some cases causing dizziness and discomfort. Here, we report on previously undescribed switchable, flat, liquid-crystal diffractive lenses that can adaptively change their focusing power. The operation of these spectacle lenses is based on electrical control of the refractive index of a 5-mum-thick layer of nematic liquid crystal using a circular array of photolithographically defined transparent electrodes. It operates with high transmission, low voltage (<2 Vrms), fast response (<1 sec), diffraction efficiency > 90%, small aberrations, and a power-failure-safe configuration. These results represent significant advance in state-of-the-art liquid-crystal diffractive lenses for vision care and other applications. They have the potential of revolutionizing the field of presbyopia correction when combined with automatic adjustable focusing power.
老花眼是一种与年龄相关的人眼调节能力丧失，表现为无法将焦点从远处物体转移到近处物体。假设没有屈光不正，老花眼患者对远处物体有清晰的视力；他们需要戴老花镜来观看近处物体。区域划分双焦点镜片是治疗这个问题的一个例子。然而，这种眼镜的视野有限，要求使用者向下凝视以完成近视力任务，在某些情况下会导致头晕和不适。在这里，我们报告了以前未描述过的可切换、平面、液晶衍射透镜，它们可以自适应地改变其聚焦能力。这些眼镜镜片的操作基于使用光刻定义的透明电极的圆形阵列对5微米厚的向列型液晶层的折射率进行电控制。它具有高透射率、低电压（<2 Vrms）、快速响应（<1秒）、衍射效率>90%、小像差以及断电安全配置。这些结果代表了用于视力保健和其他应用的最先进液晶衍射透镜的重大进展。当与自动可调聚焦能力相结合时，它们有可能彻底改变老花眼矫正领域。
