Infrared temperature sensor system for mobile devices (original) (raw)

Improved infrared temperature sensing system for mobile devices

2008

An infrared (IR) temperature measurement system consists of not only a sensor module and electronics, but also an optomechanical system that guides IR radiation onto the sensor. The geometry and emissivity of the parts affects the reading, if the detector sees not only the target but parts of the measuring system itself. In normal industrial applications, the optics is designed so that the surfaces stabilize to the same temperature as the sensor. This allows the error caused by the device temperature to be easily calibrated away. The correction is valid for stationary conditions and usually near the calibration temperature, which is typically at room temperature. However, we show that if the sensor is embedded into a mobile (hand-held) device which has heat sources, such as power electronics, the normal conditions are no longer valid and the calibration fails. In order to improve infrared temperature sensing for mobile devices, the optics concept was studied and detailed design was performed. In addition, the optics performance was modelled and verified by measurement sensor prototyping. A calibration procedure noticing operational temperature variations was applied. The repeatability of the implemented IR temperature sensor using on a correct transferred calibration curve was better than plusmn0.5degC in an operational temperature range from +12.6 to +49.3degC and target range from +10 to +90degC.

A New Thermal Infrared Camera Calibration Approach Using Wireless MEMS Sensors

2000

This work presents a unique thermal infrared (IR) camera calibration technique using wireless "smart" micro electro-mechanical (MEMS) sensors. The word "smart" denotes capabilities of MEMS other than sensing, such as, computing and communication. We foresee the use of widely distributed and deeply embedded "smart" MEMS sensors as potential calibration gauges for spectral cameras, such as, thermal IR or visible spectrum

Self-Calibrating Infrared Thermometer for Low-Temperature Measurement

IEEE Transactions on Instrumentation and Measurement, 2000

This paper presents a self-calibration technique for the removal of measurement errors caused by thermal gradients in thermopile-based infrared thermometry, particularly when measuring low temperatures. Applications for this self-calibration method include low-temperature measurement in the food industry and infrared thermometers for remote temperature monitoring in cold climates. The self-calibration technique reported in this paper is shown to reduce the measurement error to within ±1 • C within 5 s of an extreme thermal shock, compared with an uncompensated thermometer that does not recover until the thermal gradient is removed. The root-mean-square temperature noise for the duration of the thermal shock test is less than 0.2 • C. This technique is the subject of a patent application and can be applied to any infrared thermometer utilizing a thermopile, regardless of the thermopile size and geometry.

A Practical Approach of Designing Infrared Controlled Thermometer

2014

Abstract- Infrared Controlled thermometer is a non-contact temperature measurement device. The main focus of the project is to develop hardware specified design to support the infrared environment; where at the receiver end we shall be able to find the ambient temperature of that particular place. In this project the infrared ray projected from the transmitter activates the phototransistor. The signal derived from the phototransistor is amplified and decoded. This processed signal puts the relay ON. The output from the relay makes the temperature sensor operational which gives an output in form of DC voltage which is equivalent to the ambient temperature in degree Celsius. The transmitter can operate within a range of 2-6 meters.

Optimal performance of CMOS compatible IR thermoelectric sensors

… Systems, Journal of, 2000

This paper presents a theoretical and empirical study of the optimal performance of CMOS compatible infrared thermoelectric sensors with varying pixel area and different aspect ratio of the pixels for two possible sensor structures: cantilever and bridge types. Optimal performance is analyzed analytically, using simplifying assumptions. This analysis is verified by comparing with the exact simulations as well as by comparing with measured results. The resistance of optimized sensors in the sense of minimal noise equivalent power (NEP) is shown to be independent of aspect ratio, but proportional to the third root of the pixel area. The product of the optimal NEP and the square root of the time constant is shown to be constant with varying aspect ratios, while the same applies with the time constant to the power of 3/8 for varying areas.

Method of Increasing Accuracy of Infrared Temperature Measurement

Measuring Equipment and Metrology, 2019

Object temperature diagnostics by means of infrared temperature measurements as well as measurements of temperature gradients are considered. Values of the surface temperature carry information about the internal structure, defects and their location of measured object. This information becomes quite important for preventive measures and repairs of technical objects. The world production of infrared thermometers and pyrometers, thermal imagers and infrared cameras is quite significant. These measuring devices are small-sized, with low power consumption at comparatively high performance and the possibility of real-time processing information. It contributes to expanding the radiation thermometers and infrared cameras application in industry. However, low accuracy of infrared temperature measurements can lead to inadequate decisions caused by inefficient analyze of thermograms. The lack of correct information about values of impact factors including an emissivity coefficient in industrial conditions becomes a decisive. Therefore, enhancing the accuracy of temperature/temperature gradient measurements of object surface and developing of temperature measurement methodology in production cycles becomes more and more important.

Calibration and performance evaluation of an uncooled infrared thermographic system

Proceedings of the 2006 International Conference on Quantitative InfraRed Thermography, 2006

The efforts made in the last decay in the field of infrared detectors technology are mainly devoted to the development of systems of high sensitivity and performance characterized, at the same time, by low cost and simple maintenance. These goals are hardly achieved with photon detectors which, in spite of the high sensitivity and signal-to-noise performance, need to be cooled in order to operate correctly. Therefore they are often integrated in heavy and expensive instruments because of the cryogenic or thermoelectric cooling device required. For this reason, a big revolution has been achieved with the development of uncooled IR arrays, like the thermistor bolometer which is nowadays applied in most of infrared system available on the market [1]. Until the nineties this kind of thermal detector had not been exploited extensively neither in civil nor in military applications since its performance was believed to be rather poor in terms of sensitivity, time response and stability. The possibility to operate at room temperature and to offer low cost thermographic systems has instead acted as a stimulus for the applied research in this field to expend vigorous effort in order to develop new strategies to compensate the disadvantages of this kind of infrared detector. The market of infrared cameras has followed this trend, by offering as main product low-cost instruments based on the microboleter IR detector technology. The production of instruments based on the mature technology of cooled photon IR detector has instead been limited and directed to a specific market sector (mainly military or research) by causing a significant rise in their cost. This aspect may represent a problem for many research laboratories which may encounter some difficulties in purchasing high sensitivity and performance instruments. The object of the investigation here presented is to consider these aspects by means of an experimental analysis aimed to the assessment of the performance of an infrared camera having a 160 × 120 array of microbolemetric detector. The potential capability of the instrument have been verified by means of measurements taken by observing an isothermal plate of uniform emissivity in the temperaure range 10-80°C. Some representative results regarding the data acquired by viewing the plate kept at a uniform temperature of 40°C are shown in figure 1. The frequency histogram of the signal is reported both for a single image and for the image obtained by averaging 200 images acquired at a frequency of 50 Hz. The response of a single pixel in instead reported as function of time in . The application field to which the instrument performance test is addressed is quantitative measurements in the field of heat transfer. In particular the measurements are intended for anpplication of the infrared system to the estimation of the local heat transfer coefficient on thin surfaces. Regarding this specific field, Rainieri et al. have successfully developed an optimal data processing procedure, based on the Wiener filter technique, to be applied to infrared thermographic temperature maps in order to recover the heat transfer coefficient distribution on thin metallic surfaces. In this experimental investigation these Authors use an infrared camera, having a Focal Plane Array of photoemissive PtSi detectors working in the 3-5 nm spectral range and cooled to a temperature of 77 K by a Stirling cycle incorporated in the instrument, namely the PRISM DS infrared camera by Flir Systems. The same Authors have proved that a basic step in order to apply successfully the infrared thermographich technique to this specific research field, and in general in http://dx.

Design of CMOS-MEMS compatible thermopile-based infrared sensor

2017

This the aim of this project is to design an infrared detector that uses thermocouples to convert the incident infrared light into electric voltage or resistance change. Design must be CMOS compatible in order to place the evaluating electronics circuitry on the same substrate. The main tasks of the student include: • Research the literature of: o State-of-the-art infrared sensors o CMOS-MEMS manufacturing technologies o Basics of numerical simulation • Create a three-dimensional model of the infrared sensor • Simulate steady-state behavior of the microscale structure

Highly sensitive infrared temperature sensor using self-heating compensated microbolometers

Sensors and Actuators A: Physical, 2000

This paper experimentally demonstrates a novel technique that drastically reduces the self-heating effect in microbolometers and Ž. which can be used to enhance the response due to infrared IR . This is accomplished by using two bolometers with tailored thermal parameters, in particular, similar thermal mass but different thermal conductivity. Test devices with responsivity of over 6000 VrWa t bias voltage of 3 V have been fabricated. Results indicate that this method is robust even under considerable mismatch of device parameters. We believe that this technique would pave way for realization of relatively simple, low cost and sensitive IR detectors for use in thermometry, imaging and other IR applications. q

New Thermoelectric Sensor Adapted to Realize an Infrared Radiations Detector

Active and Passive Electronic Components, 2011

The present paper deals with the design and the realization of a new thermoelectric sensor (Seebeck), sensitive to the infrared radiations emitted by different sources. The function mechanism utilizes radiative absorption phenomena, heat transfer, and thermoelectric effects. The sensor includes two printed circuits, the first is a planar thermoelectric circuit constituted of many plated differential thermocouples, and the second is constituted of a resistive constantan track and placed at the top of the first circuit so that the constantan track is placed on the top of the even thermocouple junctions. The constantan track, covered with a resin of great absorptivity, collects the infra-red radiations and generates temperature gradients between the junction points of the first circuit. Then the resulting temperature differences between the junction points are directly converted into a proportional Seebeck voltage. As an application, the sensor is adapted in order to realize a device f...