FIREBIRD: Fully Integrated Bidirectional Infrared Displays

苹果（Apple） iPhone、微软（Microsoft）的多用户触摸桌（multi-user touch table）和其他类似设备的最新发展表明，人们对不依赖键盘或鼠标进行交互，而是通过直接触摸显示器进行操作的电子设备存在真正的需求。此外，在移动设备领域，能效也在不断提高。在这方面，基于有机发光二极管（OLED）技术的显示器比现有的液晶显示器（LCD）技术具有明显的优势。FIREBIRD项目旨在将多点触控表面与OLED显示屏直接集成在一起。多点触控表面将通过光学手段实现。红外OLED发射器将被布置在显示器上的矩阵中，并与一组有机光电探测器（opd）耦合。靠近显示器表面的物体会将发射器发出的红外光反射回传感器，从而进行检测。这项技术的一个关键优势是，它也可以用来识别图案表面，因此也可以用于文档扫描，例如。开发FIREBIRD多点触控显示器需要三个关键要素：OLED发射器和OPD传感器，用于驱动发射器和传感器的有源矩阵背板以及带有软件的控制器。剑桥大学工程系（CUED）在这个项目中的主要作用是开发背板技术，并与其他合作伙伴在系统集成方面进行合作。为了驱动将位于每个显示像素（显示元件，红外发射器和传感器）的各种器件，背板电子器件将需要具有良好的性能特征。氢化非晶硅（a-Si:H）已成为大面积电子产品（包括有源矩阵液晶显示器）的首选材料。然而，它存在器件稳定性差和电子迁移率差的问题。氧化锌是一种光学透明的半导体材料，可以与其他材料合金化以获得优异的电子性能。事实上，基于反应磁控溅射非晶氧化铟锌（a-IZO）的薄膜晶体管（TFT）器件已经在CUED上得到了证明，其场效应迁移率高达10 cm^2/(V)。s) -比a-Si:H提高了一个数量级。这是由epsrc资助的“剑桥光子学和电子学先进制造技术综合知识中心”（CIKC）与英国Plasma Quest Ltd. （PQL）合作资助的氧化锌tft （HiPZOT）项目实现的。在这个项目中，通过HiPZOT项目开发的平台氧化锌技术将应用于这个新的应用领域。这将需要仔细的设备开发，以确保实现多点触摸显示背板面积的要求。特别是，使用ZnO技术可以生产完全透明的tft，这将具有与显示元件集成的特殊优势。然而，人们认识到ZnO技术处于相对早期的发展阶段，因此a- si:H也将被开发以确保项目的成功，尽管这将导致最终器件的性能降低，并且不允许制造完全透明的器件。

The recent development of the Apple iPhone, Microsoft's multi-user touch table and other similar devices has shown that there is a real demand for electronic devices that do not rely on keyboards or mice to allow interaction, but which work by directly touching a display. There is also a drive towards greater energy efficiency, particularly in mobile devices, and in this regard, displays based on organic light emitting diode (OLED) technology have a clear advantage over the incumbant liquid crystal display (LCD) technology.The FIREBIRD project aims to integrate a multi-touch surface diretly with an OLED display. The multi-touch surface will be realised by optical means. Infrared OLED emitters will be arranged in a matrix over the display and coupled with an array of organic photodetectors (OPDs). Objects in close proximity to the display surface will reflect the infrared light from the emitters back onto the sensors to allow detection. A key advantage of this technology is that it can also be used to recognise patterned surfaces, and so could also be used for document scanning, for example.Three key elements are required to enable the development of the FIREBIRD multi-touch display: the OLED emitters and OPD sensors, an active matrix backplane for driving the emitters and sensors and a controller with software. The main role of Cambridge University Engineering Department (CUED) within this project will be to develop the backplane technology and to collaborate with the other partners in system integration. In order to drive the various devices that will be locted at each display pixel (display element, infrared emitter and sensor) the backplane electronics will need to have good peformance characteristics. Hydrogenated amorphous silicon (a-Si:H) has been dominant as the material of choice for large area electronics (including active matrix liquid crystal displays). However, it suffers from poor device stability and poor electron mobility. Zinc oxide is an optically transparent semiconducting material that can be alloyed with other materials to give excellent electonic properties. Indeed, thin film transistor (TFT) devices based on reactive magnetron sputtered amorphous indium zinc oxide (a-IZO) have been demonstrated at CUED with field effect mobilities ~10 cm^2/(V.s) - an order of magnitude improvement over a-Si:H. This has been enabled by a project on ZnO TFTs (HiPZOT) that has been funded through the EPSRC-funded 'Cambridge Integrated knowledge Centre for Advanced Manufacturing Technologies for Photonics and Electronics' (CIKC) in collaboration with UK-based Plasma Quest Ltd. (PQL). In this project, the platform ZnO technology that has been developed through the HiPZOT project will be applied to this new application area. This will require careful device development to ensure that the requirements of the multi-touch display backplane area realised. In particular, fully transparent TFTs can be produced using the ZnO technology, which would have particular advantages for integration with the display element. However, it is recognised that the ZnO technology is at a relatively early stae of development, and therefore a-Si:H will also be developed to ensure the success of the project, although this will lead to reduced performance of the final device and would not permit the fabrication of fully-transparent devices.