Polymer Thick Film Technology Research Articles

High-quality multimodal MRI with simultaneous EEG using conductive ink and polymer-thick film nets

Objective. Combining magnetic resonance imaging (MRI) and electroencephalography (EEG) provides a powerful tool for investigating brain function at varying spatial and temporal scales. Simultaneous acquisition of both modalities can provide unique information that a single modality alone cannot reveal. However, current simultaneous EEG-fMRI studies are limited to a small set of MRI sequences due to the image quality and safety limitations of commercially available MR-conditional EEG nets. We tested whether the Inknet2, a high-resistance polymer thick film based EEG net that uses conductive ink, could enable the acquisition of a variety of MR image modalities with minimal artifacts by reducing the radiofrequency-shielding caused by traditional MR-conditional nets.Approach. We first performed simulations to model the effect of the EEG nets on the magnetic field and image quality. We then performed phantom scans to test image quality with a conventional copper EEG net, with the new Inknet2, and without any EEG net. Finally, we scanned five human subjects at 3 Tesla (3 T) and three human subjects at 7 Tesla (7 T) with and without the Inknet2 to assess structural and functional MRI image quality.Main results. Across these simulations, phantom scans, and human studies, the Inknet2 induced fewer artifacts than the conventional net and produced image quality similar to scans with no net present.Significance. Our results demonstrate that high-quality structural and functional multimodal imaging across a variety of MRI pulse sequences at both 3 T and 7 T is achievable with an EEG net made with conductive ink and polymer thick film technology.

Influence of Various Technologies on the Quality of Ultra-Wideband Antenna on a Polymeric Substrate.

The design, simulation, realization, and measurement of an ultra-wideband (UWB) antenna on a polymeric substrate have been realized. The UWB antenna was prepared using conventional technology, such as copper etching; inkjet printing, which is regarded as a modern and progressive nano-technology; and polymer thick-film technology in the context of screen-printing technology. The thick-film technology-based UWB antenna has a bandwidth of 3.8 GHz, with a central frequency of 9 GHz, and a frequency range of 6.6 to 10.4 GHz. In addition to a comparison of the technologies described, the results show that the mesh of the screens has a significant impact on the quality of the UWB antenna when utilizing polymeric screen-printing pastes. Last but not least, the eco-friendly combination of polyimide substrate and graphene-based screen-printing paste is thoroughly detailed. From 5 to 9.42 GHz, the graphene-based UWB antenna achieved a bandwidth of 4.42 GHz. The designed and realized UWB antenna well exceeds the Federal Communications Commission’s (FCC) standards for UWB antenna definition. The modification of the energy surface of the polyimide substrate by plasma treatment is also explained in this paper, in addition to the many types of screen-printing pastes and technologies. According to the findings, plasma treatment improved the bandwidth of UWB antennas to 5.45 GHz, and the combination of plasma treatment with graphene provides a suitable replacement for traditional etching technologies. The characteristics of graphene-based pastes can also be altered by plasma treatment in terms of their usability on flexible substrates.

Electrical properties of graphite-glass thick-film resistors

PurposeThe purpose of this paper is to present the properties of thick-film resistors made of novel pastes prepared from glass and graphite.Design/methodology/approachGraphite-based resistors were made of thick-film pastes with different graphite-to-glass mass fraction were prepared and examined. Sheet resistance, temperature coefficient of resistance, impact of humidity and short-term overload were investigated. The properties of the layers fired in atmospheres of air at 550°C and nitrogen at 875°C were compared.FindingsGraphite-based resistors with various graphite-to-glass ratios made possible to obtain a wide range of sheet resistance from single O/square to few kO/square. These values were dependent on firing atmosphere, paste composition and the number of screen-printed layers. The samples made of paste with 1:1 graphite-to-glass ratio exhibited the temperature coefficient of resistance of about −1,000 ppm/°C, almost independently on the firing atmosphere and presence of a top coating. The resistors fired in the air after coating with overglaze, exhibited significantly lower sheet resistance, reduced impact of humidity and improved power capabilities.Originality/valueIn this paper, graphite-based resistors for applications in typical high-temperature cermet thick-film circuits were presented, whereas typical graphite-based resistors were fabricated in polymer thick-film technology. Owing to very low cost of the graphite, the material is suitable for low-power passive circuits, where components are not subjected into high temperature, above the typical temperature of operation of standard electronic components.

Applicability of Different Bio-based Polymers for Wiring Boards

The paper gives a review of experiments for the application of biodegradable, sustainable polymers as a wiring board material. In the paper two different biobased materials and the standard PCB materials FR4 and FR2 were compared. The investigations refer to mechanical, electrical performance, surface quality the flammability and applicability for Polymer Thick Film Technology (PTFT) of the biobased material. The biobased materials are polylactic acid (PLA) mixed with different contents of cellulose acetate (CA) or flame retardant zinc pyrophosphate (ZnPP) and polyurethane (PU) with CA. The results show that the addition of CA to the polymers leads to a change of different properties for PLA and to a significant change in mechanical properties for PU. The use of ZnPP in PLA shows major improvements regarding the flammability of the polymer. The properties of the samples are in the same order of magnitude as the properties of FR2.

Polymer thick film technology for improved simultaneous dEEG/MRI recording: Safety and MRI data quality

To develop a 256-channel dense-array electroencephalography (dEEG) sensor net (the Ink-Net) using high-resistance polymer thick film (PTF) technology to improve safety and data quality during simultaneous dEEG/MRI. Heating safety was assessed with temperature measurements in an anthropomorphic head phantom during a 30-min, induced-heating scan at 7T. MRI quality assessment used B1 field mapping and functional MRI (fMRI) retinotopic scans in three humans at 3T. Performance of the 256-channel PTF Ink-Net was compared with a 256-channel MR-conditional copper-wired electroencephalography (EEG) net and to scans with no sensor net. A visual evoked potential paradigm assessed EEG quality within and outside the 3T scanner. Phantom temperature measurements revealed nonsignificant heating (ISO 10974) in the presence of either EEG net. In human B1 field and fMRI scans, the Ink-Net showed greatly reduced cross-modal artifact and less signal degradation than the copper-wired net, and comparable quality to MRI without sensor net. Cross-modal ballistocardiogram artifact in the EEG was comparable for both nets. High-resistance PTF technology can be effectively implemented in a 256-channel dEEG sensor net for MR conditional use at 7T and with significantly improved structural and fMRI data quality as assessed at 3T. Magn Reson Med 77:895-903, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Embedded components in printed circuit boards: a processing technology review

It is evident that embedded passive components (EPCs) allow packaging substrate miniaturization and have the potential to reduce costs. Moreover, they exhibit superior electrical behaviour with respect to the minimization of parasitic effects. However, as for most emerging technologies, there is no well-established process or method for EPCs that lead to the desired result, but many have been and are still being investigated. This article attempts to review the state of the art of resistor and capacitor EPCs, including an assessment of the pros and cons of the various technologies pursued. In the review, it is found that compared to discrete surface mount devices, EPCs provide (in order of current importance): space reduction of 30% or more, better HF signal integrity and potential cost reduction. Embedded resistors in thin-film technology are, in general, restricted to small resistance values up to a few kΩ. Embedded resistors in ceramic thick-film technology require a high temperature curing process and much care during lamination, but they can be combined with embedded capacitors and exhibit high stability. Whereas embedded resistors in polymer thick-film technology require a low curing temperature and can be combined with capacitors, they exhibit poorer electrical properties and stability. Moreover, tolerances of embedded resistors after manufacturing are exceeded by 15%, independent of the manufacturing technology, which means that laser trimming is required. Embedded capacitors are based mostly on barium-titanite with a dielectric constant of only approximately 20, which limits the capacitance density to a few nF/in2. Ferroelectric material with a dielectric constant up to 2000 for embedded capacitors has been investigated but not yet established. Besides the traditional screen print technology for the deposition of pastes and inks, the ink-jet technology becomes more promising. Much higher flexibility with respect to material composition, layer thickness and even active components like LEDs have already been produced by ink-jetting.

High volume, low cost flip chip assembly on polyester flex

Polymer thick film (PTF) technology provides the lowest cost, cleanest and most efficient manufacturing method for producing flexible circuits. Non‐contact radio frequency (RF) smart cards and related information transaction devices, such as RFID tags, appear to be a good fit for PTF‐flex. Flip chip also seems well suited for these “contactless” RF transceiver products. Flip chip and PTF adhesive technologies are highly compatible and synergistic. All PTF SMT adhesives assembly methods are viable for flip chip. However, the merging of flip chip with PTF‐flex presents major challenges in design, materials and processing. This paper will compare assembly methods and discuss obstacles and solutions for state‐of‐the‐art flip chip on flex within the RFID product environment.

Development of high frequency coreless transformer using thick film polymer technology

The necessity for size decrease in power electronics systems has pushed the operating frequency of these systems into the MHz range. The operation of these systems in the MHz range introduces a number of problems such as excessive coreloss, the skin effect and the proximity effect. In this work, a new high efficiency coreless transformer has been developed using polymer thick film technology, to overcome the coreloss at high frequency. The coils of the transformer are arranged coaxially in two configurations, (1) as a one-layer structure and (2) as two series connected layers in a sandwich structure. The operating principle of this transformer is based on the skin and mutual effect between the coils at high frequency. The copper electroplating process was implemented since an upper limit exists on the thickness of the conductor due to the skin effect under high frequency operation. The well-defined geometry of this thick-film planar transformer renders the parasitic interwinding capacitance and the leakage inductance reproducible. The experimental work performed shows that the polymer thick-film transformer exhibits a low interwinding parasitic capacitance, a high coupling factor of 98% at 9 MHz and shows a maximum efficiency of 98.2% at 10 MHz depending on the load condition.

Polymer thick film technology

Polymer thick film technology

A very low-cost pressure sensor with extremely high sensitivity

Abstract A new type of piezoresistive pressure sensor has been fabricated by polymer thick-film technology. The resistor bridge is screen-printed and cured onto a flexible substrate, which has been successfully used in hybrid technology for several years. Because of the high flexibility of the substrate, high sensitivity can be achieved at low cost. During the realization, several technological problems arising from the material characteristics of the substrate have to be overcome. The most difficult one is the appropriate handling of the flexible substrate during screen-printing, curing and soldering without generating built-in stresses. This is the reason why a new technology has in fact been developed. As a result, an extremely sensitive pressure sensor has been realized at a low cost.

Polymer thick film technology in telecommunication applications : J. Cavero and A. Rodrigues. Circuit Wld18(1), 14 (1991)

Polymer thick film technology in telecommunication applications : J. Cavero and A. Rodrigues. Circuit Wld18(1), 14 (1991)

Design guidelines for polymer thick-film technology : L. Halbo, C. W. Nielsen and S. Norlying. Circuit Wld17(3), 10 (1991)

Design guidelines for polymer thick-film technology : L. Halbo, C. W. Nielsen and S. Norlying. Circuit Wld17(3), 10 (1991)

Polymer thick-film technology: A possibility to obtain very low cost pressure sensors?

Abstract A new type of pressure sensor has been developed by taking advantage of the piezoresistive effect in polymer thick-film resistors screened and cured on epoxi-glass diaphragms. The device looks promising to satisfy the requirements for low cost, high sensitivity and low thermal drift. The piezoresistive effect in polymer thick-film (PTF) resistors is discussed in comparison with cermet thick films. The possibility of making a high-performance PTF pressure sensor is theoretical supported. Characteristics of the newly developed polymer thick-film sensor are described. In a limited temperature range, the new sensor has parameters that are not worse than those of the cermet thick-film pressure sensor and a much lower cost.

Polymer Thick Film Technology in Telecommunication Applications

This paper concisely describes polymer thick film technology used with printed circuit boards as an interesting means of achieving time and cost reduction. Telephone keypads and edge connectors manufactured with this technology and using two different processes are subjected to environmental and life tests in order to compare them with the traditional gold‐plated keypads and edge connectors used in the same applications.

Seminar on the Nordic PTF project

This one‐day seminar, repeated in Sweden and Denmark, had its origins in a most interesting co‐operative project which was supported in the four Nordic countries by a total of eleven companies and research organisations. A series of six projects, each relating to a particular aspect of Polymer Thick Film Technology, was agreed by the participants, and the work programme was carried out mainly in national research institutes but with a considerable input from industrial collaborators.

PTF—a Review of Polymer Thick Film Technology

PTF—a Review of Polymer Thick Film Technology

Integration of Polymer Thick Films with PCB Technology in the Telecommunication Field

The paper describes the results obtained by the integration of Polymer Thick Film and Printed Circuit Technologies. Polymer Thick Film (PTF) Technology, applied to PCB manufacturing, helps the designer's task considerably and offers an interesting way to achieve time and cost reduction. The use of conductive and dielectric materials to generate cross‐overs and low interconnection density multilayers on epoxy‐glass substrates is shown and basic design rules are discussed. The performances of PTF conductive materials from two different suppliers are investigated in terms of conductivity, current carrying capacity and contact resistance with the copper‐clad layer. Surface and bulk insulation resistance, capacitance, loss factor and breakdown voltage are studied for dielectric materials from two different suppliers. The effects of environmental tests, i.e., thermal shocks, high temperature storage and temperature‐humidity‐bias test, on the performances of dielectric and conductive PTF are investigated by means of suitable test patterns. Application examples of Transmission System boards are discussed in terms of design and manufacturing times and costs.

Experience with polymer thick film technology: Raimo Hukkonon, Eero Jarvinen and Vesa Sortti Electrocomponent Sci. Technol. 10, 135 (1983)

Experience with polymer thick film technology: Raimo Hukkonon, Eero Jarvinen and Vesa Sortti Electrocomponent Sci. Technol. 10, 135 (1983)

Experience with polymer thick film technology : Raimo Hulkkonon, Eero Jarvinen and Vesa Sortti. Electrocomponent Sci. Technol.10, 135 (1983)

Experience with polymer thick film technology : Raimo Hulkkonon, Eero Jarvinen and Vesa Sortti. Electrocomponent Sci. Technol.10, 135 (1983)