Fast Measurement System Research Articles

Fast Optical Measurement System: Ultrafast external quantum efficiency measurements on silicon solar cells

Measuring the external quantum efficiency (EQE) of a solar cell is a standard method to gain deeper insights into its opto-electrical properties. For the case of crystalline silicon solar cells, the EQE of a solar cell is often used to assess the quality of the emitter and the passivation scheme. However, the standard EQE measurement method employs a monochromator which means that several minutes are typically needed to complete a single measurement. In academic environments this can form a bottleneck in the research output, while in industrial environments with production speeds of at least 1800 wafers/hour EQE measurements cannot be readily used. In this work, we introduce a new patented characterization tool which we call the Fast Optical Measurement System (FOMS). When using the FOMS, it becomes possible to measure the EQE of amorphous and crystalline silicon solar cells about 3 orders of magnitude faster when compared to a conventional monochromatic measurement. This means that a measurement of the full visible/near-infrared (VIS/NIR) spectrum can be done in 1–10s, without compromising on accuracy. Additionally, the FOMS can also be used to perform ultrafast reflectance/transmittance once further add-ons to the system are implemented. This opens a path to many optical applications, also outside the photovoltaics field, where fast and accurate broadband measurements are needed.

Application of fluorescence polarization immunoassay for determination of carbamazepine in wastewater

Carbamazepine is an antiepileptic drug that can be used as a marker for the cleaning efficiency of wastewater treatment plants. Here, we present the optimization of a fast and easy on-site measurement system based on fluorescence polarization immunoassay and the successful application to wastewater. A new monoclonal highly specific anti-carbamazepine antibody was applied. The automated assay procedure takes 16 min and does not require sample preparation besides filtration. The recovery rates for carbamazepine in wastewater samples were between 60.8 and 104% with good intra- and inter-assay coefficients of variations (less than 15 and 10%, respectively). This automated assay enables for the on-site measurement of carbamazepine in wastewater treatment plants.

Stereo Vision System for Accurate 3D Measurements of Connector Pins’ Positions in Production Lines

This paper addresses the need for a fast and precise non-contact measurement system to be used to assess the quality of connectors for electrical/electronic applications and particularly it proposes a technique to measure the position of the pins that are present in various shapes and number in every connector by a stereo vision system. The proposed stereo vision system is targeted to the automotive industry, but the same approach can be translated to many other sectors. The measurement of the position of the pins is a crucial aspect in assessing the quality both of the connectors (from the point of view of the connectors suppliers) and of the equipment where the connectors are used. It is of primary importance to verify the position of the pins not only in the 2D plane where they lie, but also to measure their height to verify that they can guarantee the continuity of the electrical circuit. In this paper, a technique based on the stereo vision principle is proposed to perform such an analysis. The stereo vision system, developed for a real production line, is compared against other available non-contact techniques and its advantages in terms of resolution, speed and robustness are pointed out. The system is described in terms of hardware, layout and software. System calibration and performance are described and verified. Afterwards, the on line implementation is described and the advantages and critical points are highlighted.

Fourier-transform spectral interferometry for in situ group delay dispersion monitoring of thin film coating processes.

A fast Fourier-based measurement system to determine phase, group delay, and group delay dispersion during optical coating processes is proposed. The in situ method is based on a Michelson interferometer with a broad band light source and a very fast spectrometer. To our knowledge, group delay dispersion measurements directly on the moving substrates during a deposition process for complex interference coatings have been demonstrated for the first time. Especially for the very precise production of chirped mirrors it is advantageous to get information about the phase properties of the grown layer stack to react on errors and retrieve more information about the coating process.

Compliance-Free Picosecond Smart Pulse Programming for Rram

RRAM is generally considered as the next generation of nonvolatile memory due to its simple structure, low power consumption, high-speed, high density and its compatibility with conventional CMOS processing. Another attractive feature of RRAM is its tunable resistance with applied voltage, making it a promising candidate for multi-level cell (MLC) storage and for neuromorphic computing. However, reliability and variability issues limit the potential of RRAM. Particular for MLC and neuromorphic application, poor uniformity poses as a severe hindrance. This variability is related to the stochastic nature of, filament formation, resistance switching and poor control of switching energies. While material engineering and structural optimization techniques are employed to reduce the intrinsic randomness in RRAM, these strategies are ineffective when programming energy is not under control. In this work, we propose a Compliance-free Ultra-Short Smart Pulse Programming (CUSPP) technique which offers improved control of FORMING/SET/RESET energies. This technique can potentially lead to tighter distribution of critical RRAM parameters, such as RON and ROFF, resulting in well-defined resistance window during extended cycling. CUSPP is a custom-built fast pulse-train programming and measurement system with real-time resistance sensing and automatic cycling between SET and RESET when specific resistance is reached. An ultra-short (~100 ps) pulse generator with controllable repetition rate and pulse height (up to 6V) is our source. The custom-built circuit continuously monitors the device resistance using a low DC sensing voltage to determine if the SET/RESET resistance is achieved, and to automatically change the pulse train’s height and/or polarity to enable rapidly cycling up to 2.5 million cycles per second. Unique to CUSPP measurement setup is the absence of a current limiting element such as a series resistor or transistor. The ultra-short pulse width limits the duration of current flow through the device and provide a tight control of switching energies. In the current version of the CUSPP, resistance programming is solely achieved by repetitive pulsing the device with constant pulse amplitude and pulse width. This is in contrast to many reported programming protocols where pulse amplitude and/or width are incrementally increased to reach the target resistance state. In targeting RON/ROFF, higher precision can be achieved by lowering the pulse amplitude and a concomitant higher number of pulses. Thus, high precision comes at a cost of programming speed. With the pulse repetition rate up to a few MHz this cost is entirely acceptable for mechanism studies. CUSPP is a versatile tool that can perform all essential programming of the RRAM with precision and speed while allowing the experimenter to look at the filament kinetics in details.

Evaluation of Localization Accuracy of Static Sources Using HRTFs from a Fast Measurement System

Evaluation of Localization Accuracy of Static Sources Using HRTFs from a Fast Measurement System

Anode purge strategy optimization of the polymer electrode membrane fuel cell system under the dead-end anode operation

Dead-ended anode (DEA) mode is commonly applied in fuel cell vehicles for the hydrogen purge at the anode side, to reduce fuel waste and enhance fuel cell efficiency. Anode purge is necessary and is definitely important with respect to removing liquid water and accumulated nitrogen in the gas diffusion layer and the flow field of the DEA-mode fuel cell. In this paper, the effect of different purge strategies on the stack performance and system efficiency is investigated experimentally using fast data acquisition and advanced tools, such as the fast cell voltage measurement (CVM) system and the mass spectrum. From the fast data acquisition, the voltage stability, liquid water and nitrogen concentration measurement in the anode exhaust are compared and analyzed under different purge strategy designs and using different purge valves. The results show that under the optimal purge strategy, the DEA fuel cell stack can achieve the desired stability and system efficiency based on the analysis of the cell voltage and purge volume. Moreover, the diameter of the purge valve has a great impact on the voltage stability because a diameter change will result in a different pressure drop and purge volume when the purge valve is open.

Emittance reconstruction from measured beam sizes in ATF2 and perspectives for ILC

The projected emittance (2D) and the intrinsic emittance (4D) reconstruction method by using the beam size measurements at different locations is analyzed in order to study analytically the conditions of solvability of the systems of equations involved in this process. Some conditions are deduced and discussed, and general guidelines about the locations of the measurement stations have been obtained to avoid unphysical results. The special case of the multi-Optical Transition Radiation system (m-OTR), made of four measurement stations, in the Extraction Line (EXT) of Accelerator Test Facility 2 (ATF2) has been simulated in much detail and compared with measurements. Finally a feasibility study of a multi-station system for fast transverse beam size measurement, emittance reconstruction and coupling correction in the Ring to Main Linac (RTML) of International Linear Collider (ILC) Diagnostic sections of the RTML has been discussed in detail.

Monitoring of the Dilution of Motor Oil with Diesel Using an Advanced Resonant Sensor System

In modern light-duty Diesel vehicles the particulate filters in the exhaust system require periodic regeneration to prevent plugging. The regeneration procedure is a major cause of dilution of engine oil with diesel fuel. In order to investigate the effect of the operation conditions of the engine on the fuel content in the oil, a precise and fast in-line measurement system is required. In this contribution a resonant sensor system for determination of diesel content by measuring the viscosity of the oil is tested. A commercial off-the-shelf quartz tuning fork resonator is used as sensor element and evaluated using a universal analyzer for resonant sensors developed for fast and precise acquisition of resonant sensor responses. The experiments presented in this paper show that fuel concentration in the range of 0.2 % can be determined within seconds. The obtained results are compared to that obtained with an accurate lab bench viscosity and mass density meter.

Planar near-nozzle velocity measurements during a single high-pressure fuel injection

In order to reduce the fuel consumption and exhaust emissions of modern Diesel engines, the high-pressure fuel injections have to be optimized. This requires continuous, time-resolved measurements of the fuel velocity distribution during multiple complete injection cycles, which can provide a deeper understanding of the injection process. However, fuel velocity measurements at high-pressure injection nozzles are a challenging task due to the high velocities of up to 300 m/s, the short injection durations in the $$\upmu\text{s}$$ range and the high fuel droplet density especially near the nozzle exit. In order to solve these challenges, a fast imaging Doppler global velocimeter with laser frequency modulation (2D-FM-DGV) incorporating a high-speed camera is presented. As a result, continuous planar velocity field measurements are performed with a measurement rate of 200 kHz in the near-nozzle region of a high-pressure Diesel injection. The injection system is operated under atmospheric surrounding conditions with injection pressures up to 1400 bar thereby reaching fuel velocities up to 380 m/s. The measurements over multiple entire injection cycles resolved the spatio-temporal fluctuations of the fuel velocity, which occur especially for low injection pressures. Furthermore, a sudden setback of the velocity at the beginning of the injection is identified for various injection pressures. In conclusion, the fast measurement system enables the investigation of the complete temporal behavior of single injection cycles or a series of it. Since this eliminates the necessity of phase-locked measurements, the proposed measurement approach provides new insights for the analysis of high-pressure injections regarding unsteady phenomena.

Multi-Point Stereovision System for Contactless Dimensional Measurements

The paper focuses on the design of a fast and reliable multi-point vision-based measurement system able to be flexible, low cost and accurate for quality control in industrial robotics applications. The paper discusses a new method for integrating visual quality control in highly dynamic manufacturing lines, where products are added or removed from production. The structure of the vision-based measurement system is described. In particular, the stereo system is created by the movement of a single camera mounted on a six-axis manipulator. The visual software is structured in three phases: single camera and stereo calibration, addition of the visual inspection tasks for the object to be measured, stereo measurement. The feasibility of the proposed solution has been tested in a real industrial application with strong requirements on robot speed. The comparison of experimental results on a target with a simple and well-defined shape has shown that the proposed solution provides better results, in terms of accuracy and measurement speed, when compared to commercial libraries and RGBD vision systems. Besides, the robot motion policy adopted by the solution proposed here guarantees a continuous movement without the need for stop&go phases.

Measurement Data Comparison of Fast SAR Measurement System by Probe Arrays with Robot Scanning SAR Measurement System

Dosimetry of radiating electromagnetic wave from mobile devices to human body has been evaluated by measuring Specific Absorption Rate (SAR). Usual SAR measurement system scans the volume by robot arm to evaluate RF power absorption to human body from wireless devices. It is possible to fast estimate the volume SAR by software deleting robot moving time with the 2D surface SAR data acquired by arrayed probes. This paper shows the principle of fast SAR measurement and the measured data comparison between the fast SAR system and the robot scanning system. Data of the fast SAR is well corresponding with data of robot scanning SAR within ±3 dB, and its dynamic range covers from 10 mW/kg to 30 W/kg with 4.8 mm probe diameter.

Carrier Mediated Distribution System (CAMDIS): A new approach for the measurement of octanol/water distribution coefficients

Here we present a miniaturized assay, referred to as Carrier-Mediated Distribution System (CAMDIS) for fast and reliable measurement of octanol/water distribution coefficients, logDoct. By introducing a filter support for octanol, phase separation from water is facilitated and the tendency of emulsion formation (emulsification) at the interface is reduced. A guideline for the best practice of CAMDIS is given, describing a strategy to manage drug adsorption at the filter-supported octanol/buffer interface. We validated the assay on a set of 52 structurally diverse drugs with known shake flask logDoct values. Excellent agreement with literature data (r2=0.996, standard error of estimate, SEE=0.111), high reproducibility (standard deviation, SD<0.1 logDoct units), minimal sample consumption (10μL of 100μM DMSO stock solution) and a broad analytical range (logDoct range=−0.5 to 4.2) make CAMDIS a valuable tool for the high-throughput assessment of logDoct.

Inversion of Geo-Magnetic SQUID Gradiometer Prospection Data Using Polyhedral Model Interpretation of Elongated Anomalies

This paper is based on data sets acquired by a fast and efficient ground-based measurement system, which is based on superconducting quantum interference device technology and ensures geo-magnetic mapping of large areas. The local variations (gradients) of the Earth’s magnetic field are represented in so-called magnetograms, which typically include a large number of magnetic anomalies with different appearance and shape. Here, elongated anomalies are investigated, which are explainable by a polyhedral source body. These underground structures can be represented by a cross section that is approximately uniform along the main strike extent of the source. After introducing the measurement system, a source description model is developed theoretically and in the following adapted to practical problems. In order to illustrate the utility of this kind of minimization-based inversion and to validate the produced results, an example of archaeological measurements in Mongolia is shown. Results of the field measurements are used for inversion toward a description of possible subsoil situation. Finally, an excavation shows the accuracy of the results.

Enhanced visible and near-infrared capabilities of the JET mirror-linked divertor spectroscopy system.

The mirror-linked divertor spectroscopy diagnostic on JET has been upgraded with a new visible and near-infrared grating and filtered spectroscopy system. New capabilities include extended near-infrared coverage up to 1875 nm, capturing the hydrogen Paschen series, as well as a 2 kHz frame rate filtered imaging camera system for fast measurements of impurity (Be II) and deuterium Dα, Dβ, Dγ line emission in the outer divertor. The expanded system provides unique capabilities for studying spatially resolved divertor plasma dynamics at near-ELM resolved timescales as well as a test bed for feasibility assessment of near-infrared spectroscopy.

Automatic Optical Measurement of High Density Fiber Connector

This paper will develop an automatic and fast optical measurement system for high density optical fiber connector measurement, which base on the optical project method. It will meet the lot of optical fiber connector measurement need. This system includes a high intensity and high collimated LED source, a high accuracy and high stiffness linear stage, 2 multi-degree-of-freedom adjustment mechanisms and a high resolution coaxial telecentric imaging system and image processing software. The system of measurement results and commercial measuring instruments comparing the results of its error is less than 0.6μm. To measure a V groove needs 750ms, this result may satisfy the requirements of automatic inspection.

基于Cortex-M3的快速发光二极管光电参数测量系统

According to the demands of Light Emitting Diode(LED)separation equipment for the photoelectric parameter measurement system,this paper describes a self-designed fast LED photoelectric parameter measurement system based on Cortex-M3(hereinafter referred to as M3).The system consists of an optical parameter detection module(homemade spectrometer),an electrical test module and a display module.The optical parametric module uses the M3as the main processor to acquire the spectral data and then gets the actual chromatic parameters to pass to the same M3-based processor module of electrical parameters.It greatly improves the LED parameter measuring speed and performance.Finally,without control of LED sorting machenisms,the designed LED photoelectric parameter measurement system was realized experimetally,in which the electrical testing period is less than 31ms,optical testing period can be as small as 10ms,and the deviation in consistency of chromaticity coordinate is less than 0.002 5%.

Robust white-light interferometric sensing system for fast displacement measurement

A robust white-light interferometric sensing system for fast displacement measurement is presented. In order to increase the speed of the sensing system in comparison with the standard realization based on the postprocessing of the captured interferometric signal, a real-time algorithm based on the modified centroid algorithm has been implemented. The modified centroid algorithm generates the error signal that is proportional to the interferometer optical path difference (OPD) during every scan of the used white-light source coherence zone. In order to keep zero OPD, an amplified version of the error signal has been brought to the input of the piezo bimorph actuator (PBA) that on the other side serves for the fast coherence zone scan. In this way the PBA tracks the position of the object whose displacement is to be measured. Therefore, the voltage signal at the PBA input is proportional to the measured displacement. The realized sensing system has an overall bandwidth of almost 10 Hz, where the sensor full scale range of 200 μm has been measured with a resolution of 3 nm.

Machine Vision-based Measurement System for Vehicle Body Inspection

The main contribution of the paper is to propose a system for fast and easy measurement of car body parts to support their inspection. The proposed system is composed from a camera-projector (CP) subsystem and a multi-camera and active marker based tracking system (TS). During the reconstruction process rotating gray code pattern is projected onto the targeted surface which improves the robustness and accuracy of the measurement. Afterwards based on triangulation the 3D coordinates of surface points are estimated.

Non-destructive evaluation of grain angle, moisture content and density of spruce with microwaves

Non-destructive evaluation of the physical properties of wood is a key task in modern wood manufacturing processes. Due to a rapidly increasing production speed, fast, non-contacting, reliable and robust measurement systems are demanded by the wood industry. Common moisture meters are able to reasonably cope with industrial needs. However, modern detection of wood grain angle deviation remains an unresolved issue. Microwave technology features the ability to simultaneously identify grain angle, density and moisture content of wood by measuring attenuation, phase shift, and depolarization of transmitted signals. This paper reports on series of microwave measurements revealing the desired physical properties for spruce. Samples were tested at different frequencies in the range from 8 to 12 GHz. For each frequency the grain angles were identified with standard errors of maximum 0.15° (measuring range from −90° to +90°). Standard errors in the determination of moisture density were less or equal 1.8 kg/m³ (measuring range from 27 to 56 kg/m³). Standard errors determining moisture content were maximum 0.47 % (measuring range from 7.6 to 14 %), and standard errors for dry density were maximum 11.3 kg/m³ (measuring range from 284 to 492 kg/m³).