Multi-functional ph meter and fabrication thereof

Abstract

A multi-functional PH meter and the fabrication thereof are disclosed. The multi-functional pH meter comprises a sensor unit, an analog signal processing unit, a microprocessor unit, a liquid crystal display unit, a compact flash card unit and a data transmission unit. The sensor unit includes an electrode, a substrate, an indium tin oxide film on the substrate, a sensing film on the indium tin oxide film and connecting to a conductive wire, a package material covering the sensing film, the indium tin oxide film and a portion of the substrate and exposing the sensing film via a sensing window. The analog signal processing unit processes analog signals from the sensing unit via the conductive wire. The microprocessor unit receives the signals from the analog signal processing unit and generates a pH value of a solution being detected. The liquid crystal display unit displays the pH value and the compact flash card unit saves the pH value. The data transmission unit transmits the pH value to a computer via Universal Serial Bus (USB) and Universal Asynchronous Receiver / Transmitter (UART) interfaces.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention is generally related to a multi-functional pH meter and fabrication thereof, and more particularly to a multi-functional pH meter and fabrication thereof by integrating semiconductor processes and embedded system technology.[0003]2. Description of the Prior Art[0004]Ion sensitive field effect transistors (ISFETs) are micro sensing devices appeared in 70s and quickly developed. For only 30 years till now, there are more than 600 research papers and 150 other related papers, such as enzyme field effect transistors (EnFETs) and immuno field effect transistors (IMFETs) (P. Bergveld, “Thirty years of ISFETOLOGY: What happened in the past 30 years and what may happen in the next 30 years”, Sensors and Actuators B, Vol. 88, pp. 1-20, 2003.). In addition, ion sensitive field effect transistors can be used to measure pH values and ion concentrations, such as Na+, K+, Cl−, NH4+, Ca2+, in stead of fragile gla...

AI Technical Summary

Benefits of technology

[0008]The multi-functional pH meter according to the present invention immediately displays the measurement result on a liquid crystal display and saves in a compact flash card so as to have portable functionality. In addition, the multi-functional pH meter has data communication functionality with a computer. Finally, the drift and hysteresis software calibration technique is applied. Thus, this method can increase ion detection accuracy and system reliability. The device can be applied in pH value measurement. If other polymer selection substance is used, other type of ions can also be detected and applicability is also increased. It can also increase accuracy, applicability, and industrial applications in clinics, bio-signals, and environmental detection. Because the fabrication method requires only simple equipments, is also low in cost, and can be massively produced, the multi-functional pH meter according to the present invention has very high applicability in pH value measurement.

Problems solved by technology

However, it has problems of stability and lifetime, for example drift phenomena and hysteresis effect.

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