LIQUID CRYSTALS

Author: URRUCHI DEL POZO VIRGINIA.
Year: 2003.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: ETSI TELECOMUNICACIÓN.
Place of preparation: ETSI TELECOMUNICACIÓN.

Summary: The liquid crystal flat panel displays (CL) are an evolving technology that provides a wide range of solutions to the market display devices, from low-resolution screens and low prices for watches, calculators, mobile phones or transport up screens range capable of producing high-frequency color video and high resolution. Within the high-end, highlights two trends: the average size screens and big for direct vision, and micropantallas, which can be used in projection or vision next (professional helmets, virtual reality, cabinaas steering, and so on.). A screen high resolution LC is organized in rows and columns, in the style of a matrix. The array can be active or passive, depending on whether or not possess elements of cargo storage (data). The elements used in the screens today are usually CMOS transistors and thin strain, TFT (thin film transistors). The technology involves the growth of TFT circuits silico on glass. In the case of micropantallas there is a possibility of creating active matrix in a silicon wafer, abaratándose manufacturing costs. A well developed devices are known as liquid crystal on silicon (liquid crystal on silicon, LCOS). This emerging technology can replace in the future to sTFTs in a very specific market area: miniature screens both direct view and projection and even in consumer applications such as mobile phones. Moreover, in the past five years have been developing new CL experimetnales which constitute an alternative to liquid crystals nemáticos. These materials, called esméticos chiral in response to V have the speed of response of liquid crystals nemáticos. These materials, called esmécticos chiral in response to V have the speed of response of liquid crystals ferroeléctricos and the possibility of generating grayscale low voltage analogue to the nemáticos. In this paper we have explored the possibilities of using these devices in commercial CL reflective on silicon matrix. Their potential areas of application would be conducting micropantallas for projection and direct view virtual reality environments and augmented, as well as the preparation of devices fotónicos as spatial light modulators. It has done a desk study on the formation and response electro-V materials, they have created a large number of samples in test chamber clean and these samples were characterized using a protocol of measures related to their behavior and properties; texture alignment under the microscope and thicknesses, response to low-frequency signals, generation of gray scales, and dynamic response with a frequency signals multiplexed video. Measures have also been made color final switching device. Among the most relevant results that have been achieved, one can cite the following: * Data collection and adaptation of existing models to the characteristics of our application, which has helped narrow the conditions of manufacture and sample routing electricity. * Survey and selection of materials used for alinemaiento of samples. * Developing manufacturing technologies sample reflective of 0.8 m thick, modifying it to various stages of the production line. * Design waveforms specific direcccionamiento multiplexed materials V antiferroeléctricos on silicon matrix. * Study of the influence of different parameters, such as temperature, pixel size, presence of ionic impurities and storage capacity of the condenser. * Demonstrating the feasibility of passive devices empelando arrays of silicon with external electronics. With the results, it is thought that technology can lleg 8 ar studied to be 2df a possible alternative to the technologies in use in various application fields of micropantallas.