Flexible Reflective Metasurface Displays

柔性反射式超表面显示器

• 批准号: 1509729
• 负责人: Debashis Chanda
• 金额: $ 30万
• 依托单位: The University of Central Florida Board of Trustees
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2019-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1509729&HistoricalAwards=false
• 关键词: Flexible; Reflective; Metasurface; Displays

Abstract:Non-technical: The range of colors and hues in the natural world are amazing, but perhaps even more astonishing is the ability of certain species to actively mimic them. Though the specific mechanisms are as varied as the species, each has a set of color producing cells which can span the visible spectrum. Within this vast set of creatures, cephalopods/octopi stand out as champions, who are adept to cover vast swaths of color within milliseconds. The key aspect of these color displays in nature is generation of color on a thin, flexible and conformally mapped surface whereas our manmade state-of-the art displays still remained rigid, brittle and bulky in nature. It's with cephalopods in mind that a flexible reflective metasurface display is proposed in which each pixel can be actively tuned across the visible spectrum. The proposed work is important for the development of low cost reflective displays on flexible substrates. The newly developed printing techniques will enable large area printing of nanostructured metasurfaces for low cost manufacturing. The program provides a good platform for interdisciplinary research (including integrated optics, nanofabrication and materials science and engineering) and graduate education. The research will generate exciting scientific content for enriching the PI's graduate and undergraduate teaching. The program will integrate outreach activities that span autistic students, K-12 students and other underrepresented minorities. Technical: The main focus of the proposed work is to develop an angle independent reflective metasurface with liquid crystals to achieve dynamic color tuning pixels. The implementation of dynamic pixels will reduce the need for multiple colored subpixels, thereby eliminating layered processing steps, increasing resolution, and allow unrivaled color control. Furthermore, the device will independently tune color and grey-scale within a singular liquid crystal cell through novel liquid crystal optics design and multiple electrodes. Using nanoimprint lithography to produce the plasmonic structure over large areas, one can bypass expensive and tedious electron-beam or deep-UV lithography techniques used in fabricating many previously reported plasmonic devices. This in combination with ultrafast direct laser writing, multiple features at varying size scales can be incorporated into the master patterns. A single device master can include arbitrarily pixelated plasmonic metasurface, microscopic liquid crystal cell spacers, and nanoscale liquid crystal alignment gratings. One such master can produce 100's of polymeric imprinting stamps, and one such stamp can produce 1000's of imprints without any noticeable pattern degradation. Nanoimprint lithography has also been translated to roll-to-roll processing which shows the entire fabrication process can be scaled to factory norms. There is much to understand and develop in the field of actively tunable plasmonics. A fast response, angle independent liquid crystal-metasurface based display which can actively shift the color of its pixels is achievable based on this interdisciplinary research. An in depth analysis of the plasmonic metasurface, liquid crystal orientation and how they influence each other will be studied. A key objective of the proposed system is to design a wide angle metasurface based on a specially engineered metal-insulator-metal Fabry-Perot plasmon resonance which doesn't depend on structure periodicity. While apt at producing color, these plasmonic surfaces cannot produce deep black states needed for displays due to intrinsic narrow band absorption. The proposed work intends to integrate plasmonic color tuning and liquid crystal grey state polarimetry within the same liquid crystal cell. By introducing two sets of electrodes, color and brightness can be independently tuned through a novel device design. The proposed device can readily be fabricated on flexible substrates as the low temperature fabrication process is compatible with low glassing temperature plastics. Special metasurface patterning allows device flexibility without damage to the underlying nanopatterns. Such an approach can not only lead to large area skin-like full color display elements, but can also improve the active tunability of general plasmonic metamaterial systems.

摘要：非技术性：自然界中的颜色和色调的范围是惊人的，但也许更令人惊讶的是某些物种主动模仿它们的能力。虽然具体机制因物种而异，但每个物种都有一套产生颜色的细胞，可以跨越可见光谱。在这一庞大的生物群中，头足类动物/章鱼脱颖而出，成为冠军，它们擅长在毫秒内覆盖大片的颜色。这些彩色显示器在自然界中的关键方面是在薄的、柔性的和共形映射的表面上产生颜色，而我们的人造最先进的显示器在自然界中仍然保持刚性、易碎和笨重。考虑到头足类动物，人们提出了一种灵活的反射式超表面显示器，其中每个像素都可以在可见光谱范围内进行主动调整。所提出的工作是重要的低成本的柔性基板上的反射式显示器的发展。新开发的印刷技术将使大面积印刷的纳米结构超颖表面的低成本制造。该计划为跨学科研究（包括集成光学，纳米纤维和材料科学与工程）和研究生教育提供了良好的平台。这项研究将产生令人兴奋的科学内容，丰富PI的研究生和本科生教学。该计划将整合自闭症学生，K-12学生和其他代表性不足的少数民族的外展活动。技术支持：所提出的工作的主要焦点是开发一个角度无关的反射超颖表面与液晶实现动态颜色调谐像素。动态像素的实现将减少对多个彩色子像素的需求，从而消除分层处理步骤，提高分辨率，并实现无与伦比的颜色控制。 此外，该装置将通过新颖的液晶光学设计和多个电极在单个液晶盒内独立地调节颜色和灰度。使用纳米压印光刻在大面积上产生等离子体结构，可以绕过用于制造许多先前报道的等离子体器件的昂贵且繁琐的电子束或深UV光刻技术。这与超快直接激光写入相结合，可以将不同尺寸尺度的多个特征结合到母版图案中。单个设备母版可以包括任意像素化的等离子体超颖表面、微观液晶单元间隔物和纳米级液晶对准光栅。一个这样的母版可以产生100个聚合物压印印模，并且一个这样的印模可以产生1000个压印而没有任何明显的图案退化。纳米压印光刻也被转化为卷对卷处理，这表明整个制造过程可以按工厂标准进行缩放。在主动可调谐等离子体激元领域有很多需要理解和发展的地方。基于这种跨学科的研究，可以实现快速响应、基于角度独立的液晶超颖表面的显示器，该显示器可以主动地改变其像素的颜色。深入分析等离子体超颖表面，液晶取向以及它们如何相互影响将被研究。所提出的系统的一个关键目标是设计一个广角超颖表面的基础上，一个专门设计的金属-绝缘体-金属法布里-珀罗等离子体共振，不依赖于结构的周期性。虽然易于产生颜色，但由于固有的窄带吸收，这些等离子体表面不能产生显示器所需的深黑色状态。 所提出的工作旨在将等离子体颜色调谐和液晶灰态偏振测量集成在同一液晶单元内。 通过引入两组电极，可以通过新颖的器件设计独立地调节颜色和亮度。 所提出的器件可以容易地在柔性基板上制造，因为低温制造工艺与低玻璃化温度塑料兼容。特殊的超颖表面图案化允许器件灵活性，而不会损坏底层纳米芯片。 这种方法不仅可以产生大面积皮肤状全色显示元件，而且还可以改善一般等离子体超材料系统的主动可调谐性。