High‐perform­ance Full Optics

Selec­tion of High‐perform­ance Full Optics for Optimum Image Quantity

As in the professional photography sector, beside the camera sensors used, the quality of the IR lenses is also decisive in the thermography sector for the creation of precise and detailed thermograms. The lens is a significant component of a camera system and is a decisive factor in the creation of high‐quality images or thermograms.

Optical Criteria of Infrared Optics

Distortion (optimised by the use of correction lenses, cushion‐shaped, barrel‐shaped)

Resolution capacity, modulation or contrast transmission function (MTF, resolvable line pairs per millimetre)

Vignetting (intensity drop in the corners)

Infrared Lenses for Camera Series ImageIR®

Complete Optical Assortment

High quality precision lenses allow the adaptation of the image geometry to almost every measuring situation. Its performance parameters are calibrated with respect to functionality, quality and flexible application. Due to proper IR-transparent lens materials and high-precision antireflexion coating, the lenses are optimised for different spectral ranges. Additional macro accessory lenses reduce the working distance, increase the geometrical resolution and guarantee highest imaging quality.

Why Motor Focus?

Motorised precise focusing of the image has been a standard feature of digital cameras and some mobile phones for a long time. Why not for all infrared cameras? Should this function not be automatically included in the scope of delivery?

In particular, with stationary cooled cameras like the ImageIR®, there are measurement situations in which the camera is always set up with a fixed working distance – the focus is never changed, hence, it needn't be motorised. In terms of flexible camera use, however, a motor focus is an important equipment detail that supports efficient working and the recording of the best possible measured data. The ImageIR® camera series offers a further feature that has only been implemented so comprehensively at InfraTec.

Why Motor Focus?

Motorised precise focusing of the image has been a standard feature of digital cameras and some mobile phones for a long time. Why not for all infrared cameras? Should this function not be automatically included in the scope of delivery?

In particular, with stationary cooled cameras like the ImageIR®, there are measurement situations in which the camera is always set up with a fixed working distance – the focus is never changed, hence, it needn't be motorised. In terms of flexible camera use, however, a motor focus is an important equipment detail that supports efficient working and the recording of the best possible measured data. The ImageIR® camera series offers a further feature that has only been implemented so comprehensively at InfraTec.

Innov­ative and Secure Data Trans­mis­sion Using 10 GigE Tech­no­logy

Thermographic systems are moving towards more and more increasing higher pixel numbers. Nowadays cameras are even available with detectors of up to (1,920 x 1,536) IR pixels. Not only the number of pixels has increased, but also the frame rates. For example, systems with cooled detectors (quantum detectors) can achieve full frame rates of approx. 1 kHz at an image size of (640 x 512) IR pixels. Even higher frame rates are expected in the future.

InfraTec offers the advantage of direct notebook-supported real-time data acquisition and processing. Therefore, it is absolutely necessary to achieve loss-free and reliable transmission of measurement data. Given that the advantages outweigh those of other data transmission technologies, InfraTec has decided to use the 10 GigE technology. InfraTec has raised this limit to about 1 kHz in VGA mode by means of an innovative and loss-free algorithm for data compression as well as the speed advantages of the 10 GigE interface in principle. Today's computer systems are capable of processing these data volumes without any loss. Even complex real-time image processing is feasible with these systems.

In addition, 10 GigE technology also allows secure and interference-free transfer of data generated at the highest frame rates and detector formats to a notebook computer. Thereby over several hundred metres can be bridged by using inexpensive and robust fibre optic cables (multimode). Thus, expensive and heavy CAMLink cables with limited cable length (maximum approx. 5 m) as well as expensive framegrabbers (only compatible with desktop PCs) are made a thing of the past. High-speed real-time data transmission eliminates all restrictions on system flexibility caused by limited camerainternal storage and likewise there is no need for expensive external storage media. In comparison, CoaXPress as an alternative would only allow cable lengths of approx. (30 … 40) m for the required data rates.

Over­view of Advant­ages

• Large quantities of measurement data can be stored directly on a standard notebook
• Instant data transmission with the possibility of real-time processing
• Uncomplicated data transfer over long distances feasible (up to several hundred metres)
• Mobile system concept
• Inexpensive, light, flexible and interference-proof transmission medium
• Highest frame rates without the need of camera internal memory
• No expensive Framegrabber required
• Further developments of software, firmware and peripheral technology can be implemented independently of each other, ensuring that best in class technology can be deployed in every part of the system
• In system solutions, an even higher degree of peripheral flexibility without impairing the image data throughput can be build up via individual interface solutions of a PC. This can be realised independently of the camera

Increasing the Geomet­rical Resol­u­tion with Micro­Scan

One of the key innovations of the high-end camera series ImageIR® and VarioCAM® High Definition is MicroScan. With the help of this function the number of pixels being used can be quadrupled compared to the native number of pixels of the FPA detector being used. This allows thermography of significantly higher image quality. Users can apply infrared cameras to produce thermograms with geometrical resolutions up to (2.560 x 2.048) IR pixels. Such recordings show measurement objects with a superb image quality.

The Following will be Achieved by Micro­Scan

Depending on the point of view, MicroScan has the following effects:

It...

• quadruples the number of pixels
• doubles the spatial sampling rate and thus the (spatial) Nyquist frequency of the measurement system
• divides the pixel grid in half
• reduces aliasing artefacts
• increases the quality of the images

The practical significance of the difference between the use of the native detector format of an infrared camera and the image format obtained using MicroScan can best be depicted visually. The following comparison shows the images of a Siemens star – one without and one with the MicroScan function activated. In each of the two figures two red, circular markings are shown. Inside the large circle, the frequency of the Siemens star's rays exceeds the Nyquist frequency of the detector. The smaller circle encloses the part of the Siemens-star in which the ray’s frequency exceeds the Nyquist frequency with MicroScan. For reasons of mechanical stabilization, however, the Siemens star here no longer has a ray structure, but is compact.

Figure of the Siemens star without activated MicroScan function

Figure of the Siemens star with activated MicroScan function – quadrupling the number of pixels and reducing the pixel grid by half

Aliasing and Nyquist Frequency

This example of the Siemens-star reveals the significant improvement in image quality with MicroScan. The sampling frequency of the infrared camera results from the reciprocal of the so-called pixel pitch, which is the distance between the centre of two neighbouring pixels. These are effects, which cannot be eliminated by the application of software-based filters. Aliasing occurs if the sampling rate of a measuring instrument is lower than half of the frequency of the measured signal. This frequency is called Nyquist frequency:

ƒnyquist = ½ · ƒsampling

In our application, however, this is not a temporal frequency, which is expressed in Hz, but spatial frequencies with the unit m-1 (1 / meter). The sampling frequency of the thermographic camera results from the reciprocal of the so-called pixel pitch, which is the distance between the centre of two neighbouring pixels. Assuming that this pixel pitch of a thermogram corresponds to a distance of 2 mm on the measurement object, the Nyquist frequency would be 1/2 * 1/(2 mm) = 0,25 mm-1. Structures in the object that have a periodicity < 4 mm therefore generate aliasing artefacts. Thus, the sampling frequency at which the original signal is measured, has to be more than twice as high as the highest frequency contained in the original signal ƒsignal:

ƒsampling > 2 · ƒsignal

This is How Micro­Scan Works with the Camera Series ImageIR®

In the models of the camera series ImageIR®, a fast-rotating MicroScan wheel integrated in the infrared camera ensures the practical implementation of MicroScan. Four plane-parallel windows permeable to infrared are integrated in the filter wheel, each tilted by a precisely defined angle. The tilting causes the image on the detector to be displaced laterally by half a pixel pitch for each window. These individual images are merged in real time to form a thermogram with four times the number of pixels. Each pixel in the image represents a real temperature measurement value and not an interpolated pixel.

This is not only very precise, but also very fast. How fast can be demonstrated on the example of the ImageIR® 8300 hp. If the infrared camera runs with (640 x 512) IR pixels in full frame mode at its maximum frame rate, the MicroScan wheel spins at more than 5.000 rotations per minute. Due to such high speeds, users applying MicroScan can thermographically analyze processes with fast moving targets or rapidly changing temperatures. Therefore, this technology is predestined not only for use in microthermography, but also for a wide variety of security applications.

This is How Micro­Scan Works with the Camera Series Vari­oCAM® High Defin­i­tion

In the VarioCAM® High Definition camera series the MicroScan function is implemented via a tilted germanium disc positioned between the IR detector and the optics. The disk rotates and deflects the beam path for all pixels of the sensor matrix. Four individual images, taken every quarter turn of the disk, are then combined to form a high-resolution thermal image. The offset between images is precisely defined, so that the distances between the pixels are fully filled. The fill factor, which describes the relationship between the sensitive cell and the insulation, increases to 100%. This results in a complete image of the measurement object.

Thermographic solutions ensure high quality of solar cells and modules.

• Usable for all types of solar cells and modules (silicon-based or thin-layered)
• Testing in laboratory 
• Testing of various solar cells and modules through contact and non-contact measurement
• Cell-specific system configuration and determination of test criteria and kind of defects

Flex­ible Adap­tion of the System to Types of Cells and Faults Being Tested

The construction of large-area photoelectric solar power plants requires the application of high-performance solar cells and modules of excellent quality. InfraTec's thermographic testing system PV-LIT allows testing for various types of defects – even in the manufacturing process – in different types of solar cells and photovoltaic modules. For example:

• Tandem solar cell
• III-V solar cell
• CIS solar cells
• CIGS solar cells
• Perovskite solar cells
• PERC cells (Passivated emitter rear contact)
• Organic solar cells with organic thin film foil to foil process
• Solar glass
• Smart Glass
• Electrochromatic glass

It is also possible to carry out a continuous quality control for serial productions in order to sort defective cells out at an early stage and, following, avoiding additional costs. According to the to-be-tested types of defects, PV-LIT provides the use of contact testing (DLIT) as well as non-contact testing (ILIT).

Further Features

• 100 Hz online voltage and current measurement, parallel to the lock-in excitation
• Sense-line measurement (compensation of voltage drop from the outlet)
• Power loss measurement with extended classification of shunts
• Timing diagram and export function of voltage-, current and temperature values
• Drift compensation
• Synchronized zoom the result images
• 0°/90° phase representation parallel to live and amplitude image

Modular Automated Test Bench

• Thermal analysis of electronic and semiconductor devices
• Modular test bench for online lock-in measurement
• Reliable detection of thermal anomalies in the mK and μK range
• Spatial location of defects in multilayer PCBs and multi-chip modules
• Use of thermographic systems with cooled and uncooled detectors
• Operational software IRBIS® 3 active with comprehensive analysis options in laboratory conditions 

E-LIT – Lock-In Thermography for electronics is an automated testing solution system (as part of NDT techniques) which allows non-contact (electrical) failure analysis of semiconductor material during the manufacturing process. Inhomogeneous temperature distribution, local power loss, leakage currents, resistive vias, cold joints, latch-up effects and soldering issues can be measured with Lock-in Thermography. This is achieved by using the shortest measurement times combined with a high-performance thermographic camera and a specialised lock-in procedure.

The power supply for this process is clocked with a synchronization module and failures that produce mK or even μK temperature differences are reliably detected by the Lock-in Thermography system.

Smallest defects at electronic components like point and line shunts, issues from overheating, internal (ohmic) shorts, oxide defects, transistor and diode failures on a PCB surface, in integrated circuits (IC´s), LED modules and battery cells can be detected and displayed in x and y positions. Additionally, it is possible to analyse stacked-die packages or multi-chip modules in z-direction with merely changing the lock-in frequency.

The powerful Lock-in Thermography software uses the latest algorithms and routines from most recent scientific publications.

E-LIT is extremely powerful also in resolving smallest geometrical structures as it can be equipped with strong microscopic lenses and additional SIL lenses. Identifying smallest structures with InfraTec´s E-LIT does not mean that the resulting field of view will also be smallest – implementing thermal cameras with detector sizes of up to (1,920 x 1,536) pixels provide large scale microscopic imaging. For even larger imaging stitching options are available.

Bene­fits of the Modular Test Bench

Measurement with one workstation: from the entire circuit board to the smallest detail

• Customised modular measuring station, e. g. with X-Y table and Z-axis manually or motorised adjustable, for positioning and individual adjustment of the working distances, depending on the size of the measured object
• Flexibility through variable components, e. g. different optics, holding devices for the test specimen or contacting options
• Online lock-in measurement with the highest sensitivity
• Complete and detailed microscopy analysis
• Geometrical resolution up to 1.3 μm per pixel with microscope lenses
• Thermal resolution in the microkelvin range
• Multi-layer analysis
• Automatic scanning of larger samples due to precision mechanics

Ther­mo­graphic Images with Different Optics

Tele­photo Lens 100 mm

100 mm telephoto lens with 500 mm close-up; pixel resolution 75 μm

Micro­scopic Lens 1×

1x microscopic lens; pixel resolution 15 μm

Micro­scopic Lens 3×

3x microscopic lens; pixel resolution 5 μm

Contactless measurement of temperature distributions and profiles with industrial thermographic cameras permits efficient monitoring and control of temperature-dependent processes and procedures within a system-integrated quality assurance programme in industry.

In-process Temper­ature Meas­ure­ment at its Best - INDU-SCAN 4.0

• Customised automated thermography solution based on many years of experience and intensive analysis of the respective thermal signatures by our development and application engineers
• Professional pre-analyses and selection of camera heads and optics according to strict technical measurement criteria of the inspection task ensure correct implementation
• Simultaneous, partly multi-stage multi-spot analyses, transformation and algorithmic handling of nonlinear thermal signatures and heat flows with the most modern software tools, making use of experience-based algorithms
• Technical implementation based on a flexible hardware and software kit for fast integration of customer-specific requirements
• Application of powerful, industrially proved components, that are capable of continuous use
• Selection between thermographic cameras of different performance classes and spectral ranges, application-specific protective housings and modular system control units
• Individually configurable system software for smooth interaction of all components

Flex­ible Data Inclu­sion Thanks to Industry-suit­able Inter­faces

Data and network management in the era of Industry 4.0 requires flexible and scalable system solutions that can be reliably integrated into plant and machine complexes. The transfer of digital data from cameras to process control INDU-SCAN uses modern interfaces such as GigE / 10 GigE and, if necessary, with increased transfer security or longer distances via fiber optics. The connection to the machine control is done via field bus interfaces like PROFINET, PROFIBUS, CC-Link, Modbus and others. Using TCP/IP protocol, specific quality data can be transmitted for processing and storage in central systems. Storing thermographic and other data in a database allows for a comprehensive evaluation of infrared images and sequences. Furthermore, the database offers an interface for storing the quality data in external database systems. By using these results, you can refine your documentation or based on these results directly control your processes. For this purpose, the measured values are compared in real time with defined threshold and limit values. Depending on the result, an event that has been predetermined by you will then be triggered, for example an alarm.

Being one of the largest automobile component supplier throughout the world Delphi attaches fundamental importance to the quality of its products. In Wiehl where Delphi’s laboratory plant “Test & Validation Services” is located, thermography is used for design and product validation as part of quality assurance. Therewith, a stable hardware basis is set for integrating new technologies in motor vehicles that again present a substantial contribution to traffic safety. In order to fulfil the high demands in terms of hardware, e.g. fuses, connectors and printed circuit boards, Delphi counts on efficient and exact thermographic test routines.

The laboratory plant in Wiehl has decided for the VarioCAM® series as the most suitable thermography solution because these cameras offer high flexibility. Already today, Delphi is testing products in various sizes asking for an optimal adaption of field of view and a high detail resolution. Already now small details of components and products can reliably be measured using its inbuilt close focus function. By extending the cameras with other lenses up to microscopic ones the test engineers of Delphi are also able to quickly meet emerging future demands.

But it is not just the optic design of the VarioCAM® series that convinced Alexander Ott of Delphi but also the opportunity to operate the thermal camera both handheld as well as stationary. In stationary application while the camera is being fixed on tripod and remotely controlled via a computer radiometric data can be acquired with a frame rate of up to 60 Hz without any smearing for further analysis. Therewith, even fast temperature changes can be measured with reliability and further be surveyed in detail. For analysing its data Delphi has decided for the software IRBIS® 3 plus. Thus, the time curve of a temperature distribution or the distribution of temperature changes in turn-on processes can be reviewed.

Further inform­a­tion about Vari­oCAM® series

InfraTec Solu­tion

Delphi Deutschland GmbH Test & Validation Services

www.delphi.com

Infrared camera: VarioCAM® series

5x digital zoom of thermal image with hotspot - PCB

In the image a hidden hotspot can be seen that was detected with the help of infrared thermography. In order to increase sturdiness in operation the circuit part has been revised by optimisation.

5x digital zoom of thermal image of fuse block

The image shows the temperature distribution of a fuse block.

Based on the thermal test results Delphi now benefits from reduced development times as hardware is optimally designed in the first design process already. This again results in high standards of quality and cost optimization at the same time.

High‐resolution High‐speed Thermography with ImageIR® 9300

How do solid materials change structurally? The engineers Prof. Stefan Seelecke and Marvin Schmidt from Saarland University investigate this fundamental question in materials research. Both consider this topic with the help of micro-thermography. Their cutting‐edge basic research ensures that we will have even more energy‐efficient electric devices to use at home in future.

In the last few decades, researchers have worked increasingly on alternative cooling technologies that do not use refrigerants containing fluorocarbons. Technologies such as ferroelastic cooling promise high effectiveness, a more efficient use of resources and reduction of greenhouse gas emissions. This form of cooling uses wires of a pseudoelastic shape memory alloy based on nickel/titanium (NiTi). A mechanical load on the NiTi wires causes large, reversible deformations due to a stress‐induced martensitic transformation. A martensitic structure is created, and thermal energy is given off to the surroundings. With removal of the load, the stress‐induced martensitic structure changes back into the original austenite. Thermal energy from the surroundings must be expended for this.

To achieve the maximum savings potential of ferroelastic cooling, the entire deformation process must be regulated optimally. The researchers want to control parameters independently, such as frequency or phase shift between the mechanical stress and heat transfer. In addition, they want to measure the resulting cooling performance for a specific material and a specific device geometry. To do this, Seelecke and Schmidt have developed an imaging measurement platform.

It works with an ImageIR® 9300. The high‐end thermal imaging camera is equipped with a 1x microscope lens and detects the wire to be measured, whose diameter is only approximately 150 μm. Exact thermographic temperature measurement even on longer wire sections is ensured through the geometric resolution of 15 μm. In this way, the researchers can retrace the ferroelastic cooling effects very precisely. Thanks to the camera's (1,280 x 1,024) IR‐pixel detector, the Saarbrücken‐based scientists can monitor long parts of the tiny wire and record the structural changes. The high temporal resolution of the ImageIR® 9300 of up to 106 Hz in full‐frame format also lets them follow even brief temperature changes.

Further inform­a­tion about camera series ImageIR® 9300

InfraTec Solu­tion

Saarland University
Zentrum für Mechatronik u. Automatisierungstechnik

www.zema.de

Infrared camera: ImageIR® 9300

Evaluation of the thermograms is just as sophisticated. Reflection effects and emission coefficients that are complicated to determine are among the regular challenges. Seelecke and his team therefore value the integrated correction model of the supplied IRBIS® 3. “With the software we can compensate for astonishingly many effects. That clearly makes our work easier.” The software, together with the large detector format and the high geometric, thermal and temporal resolution, forms a package that makes the ImageIR® 9300 ideally qualified for use in materials research. And by the way, this combination will hopefully do its part to ensure that we all can save more energy and protect the environment in the foreseeable future.

ImageIR® 8300 – Precise, Reliable and Efficient

At the same time that the performance of electronic components is being driven ever higher the demand for thermal management at ever smaller scales is also occurring. The Fraunhofer Institute for Silicon Technology (ISIT), as a development partner, supports companies in meeting these growing needs in an optimal fashion. As a result, the latest scientific developments can be implemented in new products very quickly, sus-taining the rapid rate of innovation required by the industry. In order to deal with this challenge, the ISIT, as well as other Fraunhofer Institutes, has a range of excellent technology. This technology enables its specialists to fulfill their tasks in the very best way.

Analysing electronic components the ISIT has to detect smallest possible temperature differences. It does so by using the thermal camera ImageIR® 8300 from InfraTec which can precisely measure temperature differences of 20 mK securely identifying any even just emerging thermal issue. Thus, development failures can be avoided at an early stage. By using a detec-tor with (640 x 512) IR pixels at a 15 µm pitch and a high performance 3x microscopic lens a geometric reso-lution of only 5 µm can be achieved. At the same time, a field of view of (3.2 x 2.6) mm2 is displayed which is suitable for many microelectronic applications. Additional, easily interchangeable lenses with a range of focal lengths enable the ISIT to further exploit the flexibility of their infrared camera across a wide variety of applications.

Another benefit for the ISIT derives from the precision calibration of the ImageIR® 8300 camera. The use of a set of additional side calibration curves compensates for drift and ensures a maximum measurement accuracy even under fluctuating measurement conditions. As with all thermographic testings of electronic components and circuits, measurements are influenced by the differing emissivity of the individual components. To overcome this situation, InfraTec offers an automated pixel wise emissivity correction routine directly in its control and analysis software IRBIS® 3. Using these tools precise statements can be made about temperature distributions and developments over time. With the time component of the heating playing an increasingly important role in the ever decreasing sizes of components, the ISIT is able to take advantage of the multi-kHz frame rates possible with the ImageIR® 8300.