Digital Imager Enhancement and Investigating Grayscale Photomasks Technologies for Fabrication of Micro-optics

新的微加工技术对社会产生了巨大的影响，将微芯片转化为数字成像传感器和微光学器件。从科学仪器到商业摄影，成像传感器现在用于将传感器与微光学器件和控制电子器件集成到单个芯片上。这项研究结合了光电子学（电子学和光学的结合）和纳米纤维学这两个领域，纳米纤维学是用于构建微光学的技术。 1)在光电子学方面，我的研究小组专注于相机中的数字像素阵列。随着时间的推移，成像仪会产生越来越多的缺陷，从而降低图像质量并缩短传感器寿命。使用商业相机图像和软件分析算法，我们研究缺陷的发展，以确定故障像素的特点，并查明因果机制。研究将改进已开发的公式，这些公式显示出更大的传感器面积、更高的灵敏度和缩小的像素尺寸的趋势，从而在缺陷强度和发展速度方面都产生指数增长，每年可以达到1000个缺陷。我们将研究应用程序，如新的方法来改善图像修复的基础上，使用有关缺陷参数的知识，软件校正像素，创建参数，以提供更好的指标，选择相机在高辐射环境，如空间站，并使用这些缺陷模式和参数，以创建一个相机独特的“指纹”的法医鉴定在安全和刑事调查。 2)在纳米制造中，我们研究了灰度光掩模的制造，这是一种对具有成本效益的3D结构至关重要的技术。现有的商业灰度掩模要么在透明度控制方面非常有限，要么精确但非常昂贵。我们正在开发铋、铟和锡的纳米薄膜，形成一种在激光曝光下氧化并变得透明的热抗蚀剂。通过改变这些胶片上的激光功率的设备，将开发出直接写入灰度光掩模，其在低成本掩模中将透明度控制到高精度（256步）。由于掩模透明度只是微结构垂直控制能力的一个限制因素，因此我们将联合收割机与新的制造方法相结合，将这些图案转移到微光学非常精确的3D结构的创建中。微光学应用需要高度精确的形状来创建适当的光学图像。我们的研究还打算将这种方法应用于创建微光学器件，用于提高相机像素，创建扭曲较少的薄菲涅耳透镜和用于抬头显示器的薄伽柏透镜。在微流体设计中，我们将在具有独特流体混合特性的微通道中创建3D形状，并将微光学集成到基于荧光的芯片实验室系统中。

New microfabrication techniques have had a dramatic impact on society, by transforming microchips into digital imaging sensors and micro-optics. From scientific instrumentation to commercial photography, imaging sensors are now used to integrate sensors with micro-optics and control electronics onto single chips. This proposed research combines the two areas of opto-electronics (the combination of electronics and optics) and nanofabrication, the technique used to build the micro-optics. 1) In opto-electronics my research group focuses on digital pixel arrays in cameras. Imagers develop a growing number of defects over time that degrades image quality and reduces the sensor life. Using commercial camera images, and software analysis algorithms, we study defect development to identify faulty pixels characteristics, and pinpoint the causal mechanism. Research will improve developed formulas that show the trend towards larger sensor area, higher sensitivity and shrinking pixel size creates exponential growth in both defect strength, and development rates, which can reach 1000’s of defects per year. We will investigate applications such as novel ways to improve image repair based on software-correcting pixels that use knowledge about the defect parameters, creating parameters to give better metrics for choosing cameras in high radiation environments like the Space Station, and using these defect patterns and parameters to create a camera-unique “fingerprint” for forensic identification in security and criminal investigations. 2) In nanofabrication, we investigate the fabrication of grayscale photomasks, which are a technology critical to cost-effective 3D structures. Existing commercial grayscale masks are either very limited in transparency control or accurate but highly expensive. We are developing bimetallic thin films of Bismuth, Indium and Tin, forming a thermal resist which oxidizes and becomes transparent under laser exposure. With equipment that varies the laser power on these films, direct-write grayscale photomasks will be developed which the control transparency to a high accuracy (256 steps) in a low cost mask. Since mask transparency is only one limiting factor in the vertical control ability of microstructure, we will then combine this new mask with new fabrication methods to transfer these patterns into the creation of very accurate 3D structures for micro-optics. The micro-optic application requires highly precise shapes to create the proper optical images. Our research also intends to apply this method to the creation of micro-optics for applications in improving camera pixels, creating less distorting thin Fresnel lenses, and a thin Gabor lens for heads-up displays. In microfluidic designs, we will create 3D shapes in microchannels with unique fluid mixing properties and integrate micro-optics into fluorescence based lab-on-a-chip systems.