No abstract

Functionally graded ferroelectric ceramics (FGM) have been fabricated for pyroelectric applications by an aqueous tape casting technology. The FGM produced in this study consisted of a porous Lead Zirconate Titanate (PZT) tape-cast ceramic, which was made by starch inclusions; sandwiched between two dense PZT layers by stacking and lamination. This paper investigates the effect of porosity on the microstructure and electrical properties of the PZT FGM samples produced. The microstructure of the porous and laminated sintered structures was studied using Scanning Electron Microscopy (SEM). The grain size of the porous layer tended to decrease with increasing corn-starch content. The dielectric constant and pyroelectric coefficient of the FGM both showed decreasing behaviour with increasing porosity.

Pyroelectric infra-red detector arrays provide an attractive solution to the problem of collecting spatial information in the far IR. They are only sensitive to changes in the IR flux and are well suited to sensing movements of people. The applications of low cost arrays with limited (few hundred) elements for people sensing & radiometry will be illustrated. The performances of uncooled pyroelectric arrays are ultimately driven by the materials used. For this reason, continuous improvements in materials technology and figures-of-merit are important. The performance of dense, bulk pyroelectric ceramics has not increased for several years, but nevertheless it is possible to obtain significant improvements in performance thorugh the use of tape-cast, functionallygradient materials (FGMs) in which controlled porosity is used to control the permittivity and heat capacity of the material. A model for the performance of such a material will be presented, and compared with experimentally-determined properties of FGMs based on a modified-PZT pyroelectric ceramic. The use of ferroelectric thin films is offering considerable potential for low cost & high performance. It will be shown that the introduction of controlled amounts of porosity can have a significant positive effect on the relevant pyroelectric figure-of-merit.

Abstract. The paper presents the findings of a survey of 40 microsystems companies that was carried out to determine the use and the purpose of use of media forms and information flow models within these companies. These companies as 'product-service systems' delivered integrated products and services to realise customer solutions. Data collection was carried out by means of an online survey over 3 months. The survey revealed that 42.5% of respondents made use of data flow diagrams and 10% made use of design structure matrices. The survey also suggests that a majority of companies (75%) made use of textual and diagrammatic media forms for communication, analysis, documentation and representation during design and development processes. The paper also discusses the implications of the survey findings to product-service systems.