Light addressable potentiometric sensor array: A new approach for light beam positioning

Abstract

An analytical system for multicomponent analysis of liquids based on a light addressable potentiometric sensor (LAPS) with an array of ion-sensitive polymer membranes is presented. A developed LAPS device is based on a BESOI wafer which permits easy fabrication of a sensor with thin silicon membrane and enhanced spatial resolution. To generate the photocurrent the backside silicon was illuminated using a new technical approach based on a DLP (Digital Light Processing) chip used in video projectors. When a DLP chip is coordinated with a digital graphic signal, a light source, and a projection lens, its mirrors can reflect a digital image onto the LAPS surface. The developed system is shown to be able to produce light spots down to 50 μm in diameter and perform measurements at different points with programmable coordinates. To prove the functionality of the proposed method a LAPS sensor array with 60 ion-sensitive membranes of three different types was tested.