Publication: Contribución al desarrollo de nuevas ayudas electroópticas en rehabilitación visual
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2015
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2015-12-15
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Abstract
Aunque no haya un total acuerdo entre los profesionales de la oftalmología, algunas investigaciones han mostrado que el uso de filtros, al eliminar ciertas longitudes onda, podría ser muy beneficioso para todo tipo de personas. Desde aquellos que simplemente los quieran usar como gafas de sol de coloración variable, hasta personas con baja visión cuya patología los hace extremadamente sensibles a cambios bruscos de luz-oscuridad. Estas personas necesitan llevar siempre consigo una serie de filtros, normalmente entre dos y cuatro, con el inconveniente que esto les genera. En la actualidad sólo existe una solución comercial de funcionamiento similar, las lentes fotocromáticas, las cuales cambian de coloración al recibir radiación ultravioleta. Esto significa que cambian de color con la incidencia directa de radiación solar, pero no funcionan en lugares donde esta radiación no existe, como interiores, o donde llega filtrada, como en el interior de la mayoría de los coches. Además presentan otro inconveniente: su baja velocidad de conmutación, siendo del orden de varios minutos. Los dispositivos electrocrómicos han sido usados e incluso comercializados, en los últimos años, como ventanas inteligentes o como retrovisores en los coches. Sin embargo, su uso como filtros ópticos para la visión, aunque se ha intentado desde de los años ochenta, no ha llegado nunca a comercializarse. En esta tesis se ha desarrollado un sistema capaz de aplicar diferentes algoritmos, configurables mediante una interfaz de usuario, a un cristal electrocrómico. El sistema almacena automáticamente, la tensión aplicada, la transmitancia, la temperatura y la corriente consumida, en uno o varios ficheros compatibles con Microsoft Excel para su posterior procesado. Se describirán los resultados de distintos algoritmos aplicados a cristales electrocrómicos viológenos de diversos espesores. Se mostrarán tiempos de respuesta, variación de la transmitancia, consumo eléctrico y ciclabilidad, con el objetivo de aplicar el algoritmo óptimo en relación con su consumo/tiempo de conmutación/ciclabilidad sobre los cristales de un nuevo dispositivo de ayuda a la visión desarrollado por el autor del presente trabajo. Se mostrarán tiempos de respuesta ostensiblemente mejores que los de las lentes fotocromáticas. También se mostrará cómo es posible integrar la electrónica en una montura de gafas similar a las actuales soluciones comerciales.
In spite of the fact that there is no full agreement among eye care professionals, research has shown that using filters to remove certain wavelengths could be very beneficial for all kinds of people: from those who only want to use them in variable coloration sunglasses, to people with low vision, whose pathology makes them extremely sensitive to sudden changes in light conditions. That people always need to wear a whole series of filters, usually between two and four, with the inconvenience that this may cause them. Currently, there is only one marketed similar solution: photochromic lenses, which change its color when receive ultraviolet radiation. This means that the color change is made by means of sunlight direct contact, but do not work in places where the sunlight radiation does not exist, as indoors, or where it is filtered, such as inside most cars. Furthermore, photochromic lenses present another disadvantage: its low switching speed, spending several minutes to change its state. Electrochromic devices have been used and even marketed for the last years, both as smart windows and rear mirrors in cars. However, its use as optical filters for viewing has never been marketed, although it has been attempted since the eighties. In this thesis a new characterization system has been developed so as to apply different algorithms, which are configurable through a user interface, to electrochromic devices. Moreover, the system, automatically, stores the applied voltage, transmittance, temperature and electric current in one or more files compatible with Microsoft Excel for further processing. Thus, the results from different algorithms applied to electrochromic devices with different thicknesses will be described. Response times, transmittance variation, power consumption and cyclability will be shown, in order to apply the optimal algorithm, regarding with its consumption, switching time and cyclability, on crystals of a new technical aid device for low vision, developed by the author of this work. Not only better response time than photochromic lenses will be demonstrated, but it will be also shown how electronics can be integrated in a frame similar to current market solutions glasses.
In spite of the fact that there is no full agreement among eye care professionals, research has shown that using filters to remove certain wavelengths could be very beneficial for all kinds of people: from those who only want to use them in variable coloration sunglasses, to people with low vision, whose pathology makes them extremely sensitive to sudden changes in light conditions. That people always need to wear a whole series of filters, usually between two and four, with the inconvenience that this may cause them. Currently, there is only one marketed similar solution: photochromic lenses, which change its color when receive ultraviolet radiation. This means that the color change is made by means of sunlight direct contact, but do not work in places where the sunlight radiation does not exist, as indoors, or where it is filtered, such as inside most cars. Furthermore, photochromic lenses present another disadvantage: its low switching speed, spending several minutes to change its state. Electrochromic devices have been used and even marketed for the last years, both as smart windows and rear mirrors in cars. However, its use as optical filters for viewing has never been marketed, although it has been attempted since the eighties. In this thesis a new characterization system has been developed so as to apply different algorithms, which are configurable through a user interface, to electrochromic devices. Moreover, the system, automatically, stores the applied voltage, transmittance, temperature and electric current in one or more files compatible with Microsoft Excel for further processing. Thus, the results from different algorithms applied to electrochromic devices with different thicknesses will be described. Response times, transmittance variation, power consumption and cyclability will be shown, in order to apply the optimal algorithm, regarding with its consumption, switching time and cyclability, on crystals of a new technical aid device for low vision, developed by the author of this work. Not only better response time than photochromic lenses will be demonstrated, but it will be also shown how electronics can be integrated in a frame similar to current market solutions glasses.
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Optoelectrónica, Oftalmología, Lentes fotocromáticas, Cristales electrocrómicos, Rehabilitación visual