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MICRO-DISCHARGE BASED GAS SENSOR

IP.com Disclosure Number: IPCOM000199109D
Publication Date: 2010-Aug-26
Document File: 7 page(s) / 203K

Publishing Venue

The IP.com Prior Art Database

Abstract

A micro-discharge device which senses gases particularly smoke or CO/ CO2 is disclosed. The micro-discharge device includes a refractory / ceramic for example, zirconia spheres and meshes electrodes. The micro-discharge cavities based on the ceramic/refractory/dielectric spheres are used to generate optical signals corresponding to the gas that needs to be detected. The micro-discharge based ionization ensures uniformity, lower cost and environment friendly, as no radioactive materials are required.

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Page 1 of 7

RP13494

BRIEF ABSTRACT

    A micro-discharge device which senses gases particularly smoke or CO/ CO2 is disclosed. The micro-discharge device includes a refractory / ceramic for example, zirconia spheres and meshes electrodes. The micro-discharge cavities based on the ceramic/refractory/dielectric spheres are used to generate optical signals corresponding to the gas that needs to be detected. The micro-discharge based ionization ensures uniformity, lower cost and environment friendly, as no radioactive materials are required.

KEYWORDS

    Microdischarge, microplasma, flexible, low power, uniform discharge, gas sensors, microcavity, dielectric and ionisation

DETAILED DESCRIPTION

    Current technologies related to gas sensing, particularly smoke or CO / CO2 sensors, involves solid state, radiation, or electrochemical processes. The parameters, such as electrical resistivity or wavelength of light are commonly measured in these sensors. The processes associated with these sensors are ionization, chemi- / physi-sorption, or oxidation, etc. However, these gas sensors suffer from one or more adverse factors, such as poor accuracy, slower sensing speed, fault sensing and higher cost.

    Therefore, there is a need in the art for a micro-discharge gas sensor which renders high uniformity in the discharges, involves lower cost and is environment friendly with a potential to extend for many other applications.

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MICRO-DISCHARGE BASED GAS SENSOR

Page 2 of 7

RP13494

    The present invention discloses a micro-discharge device which includes a semiconductor layer (cathode) with a tapered cavity disposed therein, an intermediate layer (dielectric layer) and a conductive metallic layer (anode) as depicted in Figure 1. Tapered cavities are relatively inexpensive, and easy to fabricate using conventional semiconductor processing techniques. Thus the present invention is cost effective and offers better electrical and optical characteristics with a longer life span.

    The present device constitutes refractory / ceramic for e.g. ZrO2 (zirconia) spheres with ~ 1mm diameter configured in an array with mesh electrodes as shown in Figures 2 and 3. Micro-discharge cavities based on the ceramic or refractory or dielectric spheres are used to generate optical signals corresponding to the gas that needs to be detected. A high uniformity in the discharges is observed with 5 kHz/AC frequency compared to AC-50Hz or DC.

    Figure 4 depicts typical V-I waveforms and the optical spectrum of...