Application of an IR Thermographic Device for the Detection of a Simulated Defect in a Pipe

et al. 2012

Sensors

A method of measuring the precise temperature distribution of GaN-based light-emitting diodes (LEDs) by quantitative infrared micro-thermography is reported. To reduce the calibration error, the same measuring conditions were used for both calibration and thermal imaging; calibration was conducted on a highly emissive black-painted area on a dummy sapphire wafer loaded near the LED wafer on a thermoelectric cooler mount. We used infrared thermal radiation images of the black-painted area on the dummy wafer and an unbiased LED wafer at two different temperatures to determine the factors that degrade the accuracy of temperature measurement, i.e., the non-uniform response of the instrument, superimposed offset radiation, reflected radiation, and emissivity map of the LED surface. By correcting these factors from the measured infrared thermal radiation images of biased LEDs, we determined a precise absolute temperature image. Consequently, we could observe from where the local self-heat emerges and how it distributes on the emitting area of the LEDs. The experimental results demonstrated that highly localized self-heating and a remarkable temperature gradient, which are detrimental to LED performance and reliability, arise near the p-contact edge of the LED surface at high injection levels owing to the current crowding effect.

Section: Introductionmentioning

confidence: 99%

Precise Temperature Mapping of GaN-Based LEDs by Quantitative Infrared Micro-Thermography

Chang

Yang

et al. 2012

Sensors

“…In the previous applications of the IR thermometers for the defect detection [11, 12] a uniform heating was utilized, but the heating is difficult to apply in a practical implementation. As demonstrated in this study, the point heating on a localized spot in a vessel wall is more practical than the uniform heating and is effective to detect a defect.…”

Section: Resultsmentioning

confidence: 99%

“…Because its measurement range of temperature is limited and the distance between the sensor and measured object is critical to the measurement, a specially designed sensor module is necessary for the adjustment of the range and distance. The technique has been applied to the detection of simulated defect in a plate [11] and a pipe [12] showing the ability of defect detection of the system.…”

Section: Introductionmentioning

confidence: 99%

Detection of Simulated Defect Using IR Temperature Sensors and One Point Heating

Heo

Suh

et al. 2008

Sensors

Self Cite

Infrared temperature sensors, simple device for temperature measurement, have been modified for the measurement of temperature distribution on the metal surface in a way of nondestructive detection of defects of the object. In this study, the IR sensor system is utilized for the defect detection in a cylinder with one point heating, and the performance of the system is examined with an aluminum cylinder having a simulated defect. In addition, a 3-D conduction equation is numerically solved to compare the computed temperature profile with the measured one. The experimental outcome indicates that the defect detection is readily available with the proposed device and the point heating is practical for the applications of the defect detection. It is also found that the measured temperature distribution is comparable to the computed result from the conduction equation.

“…In the previous applications of the IR thermometers for the defect detection [3,4] a uniform heating was utilized, but the heating is difficult to apply in a practical implementation. As demonstrated in this study, the point heating on a localized spot in a vessel wall is more practical than the uniform heating and is effective to detect a defect.…”

Section: Resultsmentioning

confidence: 99%

Defect detection in a cylinder using an IR thermographic device and point heating

Jeong

2007 International Conference on Control, Automation and Systems

2007

An infrared temperature sensor is a simple device for temperature measurement, and has been modified for measuring temperature distribution of metal surface in a way of nondestructive detection of defects in metal objects. In this study, the IR sensor application is modified for the defect detection in a cylinder with one point heating, more convenient than uniform heating as applied in the previous studies. The experimental outcome with the proposed technique indicates that the detection of a simulated defect is possible and the point heating is more practical than the uniform heating for the field apphcation. It is also found that the measured temperature distribution is comparable to the computational result from a heat conduction equation.