ECE5320 Mechatronics Infrared Emission Thermometers

1. ECE5320 MechatronicsInfrared Emission Thermometers Prepared by: Augusto Rodríguez Dept. of Electrical and Computer Engineering Utah State University deleon.augusto@gmail.com; (435) 213-1185 3/6/2009

2. Outline • Reference list • To explore further • Major applications • Basic working principle illustrated • A typical sample configuration in application (application notes) • Major specifications • Limitations • How to choose an IR thermometer • Cost ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

3. Reference list • [1]Mechatronics Handbook, The. Robert H. Bishop. • [2]Measurement, Instrumentation and Sensors Handbook, The. John G. Webster. • [3]Use Of Infrared Emission Detection Thermometer. The Hong Kong College of Family Physicians. • [4]http://www.pyrometer.com/processheating.html • [5] http://www.evergreenengineering.com ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

4. To explore further • The Accuracy of Oral Predictive and Infrared Emission Detection Tympanic Thermometers in an Emergency Department Setting. • http://www3.interscience.wiley.com/cgi-bin/fulltext/119827218/PDFSTART • Infrared thermometer with automatic calibration. • http://www.google.com/patents?hl=en&lr=&vid=USPAT4784149&id=hEEvAAAAEBAJ&oi=fnd&dq=infrared+emission+thermometers. • Sensitivity of simple infrared thermometers. • http://www.iop.org/EJ/article/0022-3735/16/7/012/jev16i7p613.pdf?request-id=d0aa9b0e-c47a-4d7e-9be4-39f8d5106dd1 ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

5. Major applications • Temperature measurement of semiconductor materials during fabrication process. • Sometimes it is necessary to coat the semiconductor with a high emissive material due to the low emissivity of the semiconductor. Wafer, semiconductor[5] ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

6. Major applications • Medical applications: • Skin temperature measurement. • Body temperature measurement. Sometimes, this is measured by getting the tympanic membrance temperature. • Detecting clouds for remote telescope operation. • Checking mechanical equipment or electrical circuit breaker boxes or outlets for hot spots. • Checking heater or oven temperature, for calibration and control purposes • Detecting hot spots / performing diagnostics in electrical circuit board manufacturing • Checking for hot spots in fire fighting situations • Monitoring materials in process of heating and cooling, for research and development or manufacturing quality control situations ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

7. Basic Working Principle • IR emission thermomethers are classifiead as non-contact thermometers since they don’t need to be in contact with the object being monitored. • These sensors work based on the infrared emissions from the object being measured. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

8. Basic Working Principle • IR Emission Thermometers work based on the principle that all objects whose temperature is above the absolute zero radiate electromagnetic waves whose spectrum is associated to its surface temperature. • Ideally, an IR thermometer consist of a sensor and a detector. • The sensor monitors the temperature of a detector. • The detector gets the radiative heat transfer of the object’s surface. • However, the detector has loss and its range of sensing is not restricted to the object being measured. • Optical devices are used to limit the range of the detector to the object being measured. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

9. Basic Working Principle The operating principle of the IR thermometer is based on Stefan-Boltzmann law: • Where: • Tc is the object’s temperature in Kelvin. • is the net thermal radiation flux. • Ts is the sensor’s surface temperature • :Emissivity of the object. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

10. Basic Working Principle Simple diagram of IR a thermometer [4]. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

11. A typical sample configuration • Measuring the temperature of a semiconductor material during fabrication. Diffused-light thermometer for measuring temperature of GaAs wafers [2]. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

12. Major Specifications • Response time: • IR thermometers’ response time is around one second, which is relatively fast. However, their warm up time is relatively large. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

13. Major Specifications • Electromagnetic Spectrum: the infrared thermometers measure the temperature in the range of 0.7 to 80 µm. IR Spectrum [4]. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

14. Major Specifications • Materialsused. [2] ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

15. Major Specifications • Temperature error: • Uncertainties in the emissivity of the object to measure may result in errors in the measured temperature. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

16. Limitations • There is a limited variety of lenses an filter that can be choosen to build IR Emission Termometers. • IR refractive materials have high absorption of light. Thus, there is a limitation with lenses since they need to be relatively thick. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

17. How to choose an IR Emission Thermometer • Several factors have to be taken into account before selecting an IR termometer: • Distance to object. • Target temperature range. • Object’s material. • Object’s size. • Ambient temperature. • Gases that might be interfering. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators

18. Cost • Depending on the added features and manufacturer, cost may vary from USD $2, 000 to USD $50.00 They can be easely bought online. ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators