Results 161 to 170 of about 5,622 (205)

Applications of pulse heating thermography and lock-in thermography to quantitative nondestructive evaluations

Infrared Physics and Technology, 2002
This paper describes several experimental investigations of newly developed thermographic NDT techniques based on the transient temperature measurements. Several experimental results of the pulse heating thermographic NDT and the lock-in thermographic NDT are shown.
Takahide Sakagami, Shiro Kubo
exaly   +2 more sources

Thermal diffusivity of metals determined by lock-in thermography

Quantitative InfraRed Thermography Journal, 2017
Lock-in infrared thermography is a well-established technique for measuring the thermal diffusivity of materials.
Peter Nolte, Timo Malvisalo, Stefan Schweizer   +2 more
exaly   +2 more sources

Lock-in thermography for investigating solar cells and materials

Quantitative InfraRed Thermography Journal, 2010
For more than 10 years lock-in thermography (LT) is being used for investigating leakage current phenomena in solar cells. In operation the p-n junction of a solar cell is forward-biased. So-called local shunts are leakage sites which cause losses in efficiency. They can be investigated by applying a pulsed forward-bias to the cell in the dark (typical
Otwin Breitenstein
exaly   +2 more sources

Multiplexed lock-in thermography

Review of Scientific Instruments, 2021
Many modern measurement methods for heat transfer work in the frequency domain. A certain average temperature rise in the sample is unavoidable if the sample can only be heated, e.g., by an intensity modulated light source. This average temperature rise influences the measured thermal properties because they are, in general, temperature dependent. Here,
Bernd A. F. Kopera, Markus Retsch
openaire   +2 more sources

Defect Localization by Lock-In-Thermography

International Symposium for Testing and Failure Analysis, 2022
Abstract This presentation provides an overview of lock-in thermography and its application in semiconductor failure analysis. It begins with a review of direct thermal imaging, IR transmission and detection, and the fundamentals of lock-in measurements.
openaire   +1 more source

Glued structures inspection based on lock-in thermography

SPIE Proceedings, 2015
Active thermography is a widely employed technique for parametric identification and non-destructive inspection. This attractive method is based on the observation of thermal waves propagation induced by a periodic heating. For nondestructive testing usual approaches are based on a global heating (a large surface of the inspected material is submitted ...
Perez, Laetitia, Autrique, Laurent
openaire   +2 more sources

THE USE OF LOCK-IN THERMOGRAPHY IN INDUSTRIAL APPLICATIONS

Nondestructive Testing and Evaluation, 2000
Abstract A feasibility study is made to search if lock-in thermography can be usefully employed in non-destructive evaluations of different materials of industrial interest. Several specimens, made of different materials and with defects artificially created to simulate either delaminations, or cracks, or inclusions of spurious materials, are ...
GIORLEO, GIUSEPPE, MEOLA, CAROSENA, SQUILLACE, ANTONINO   +2 more
openaire   +3 more sources

3D Hot-Spot Localization by Lock-In Thermography

EDFA Technical Articles, 2019
Abstract This article describes a form of lock-in thermography that achieves 3D localization of thermally active defects in stacked die packages. In this approach, phase shifts associated with thermal propagation delay are analyzed as a function of frequency.
Sebastian Brand, Frank Altmann
openaire   +1 more source

Defect detectability based on square wave lock-in thermography

Applied Optics, 2022
A lock-in thermography technique based on a periodical square wave is used to detect stainless steel plates with defects. Combining a neural network with lock-in thermography, an image processing technique is proposed, and the results are compared with traditional image processing methods.
Pengfei, Zhu, Dan, Wu, Yifan, Wang, Zhifei, Miao   +3 more
openaire   +2 more sources

Absorption measurements in optical coatings by lock-in thermography

Applied Optics, 2017
We evaluate and apply lock-in thermography as a method to quantitatively evaluate absorption losses of optical coatings. The principle of the method consists of applying periodically modulated laser intensity on the coatings and to monitor the periodic surface temperature evolution with an infrared camera.
Liu, Feng, Gallais, Laurent
openaire   +3 more sources