High-speed non-contact sheet resistivity monitoring of printed electronics using inductive sensors

Lewis, A. H.; Hunt, C; Thomas, Owen; Wickham, M

doi:10.1088/2058-8585/aa9875

Cited by 6 publications

(7 citation statements)

References 17 publications

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“…Non-destructive testing (NDT) using capacitive and eddy current sensors is broadly used for defect detection in semi-finished products, e.g. wires, bar, and tubes in the production line [93,103,104]. Seong et al [93] uused a combination of two sensors for in-line and non-contact thickness measurements of conductive ink adaptable to an industrial printing process such as R2R.…”

Section: Eddy Current Testingmentioning

confidence: 99%

See 1 more Smart Citation

Towards in-situ quality control of conductive printable electronics: a review of possible pathways

Zhuldybina¹,

Ropagnol²,

Blanchard³

2021

Flex. Print. Electron.

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Over the past decade, printed electronics (PE) has shown great potential for a wide range of industries, from consumer goods, electronics, aerospace, automotive, pharmaceutical, biomedical, to textiles and fashion. The rapid development of printing technology has been strongly driven by the growth of the PE market and its many applications. Here, we review the latest trends in PE production quality control, focusing on emerging technologies such as terahertz spectroscopy, which may play a key role in the development of smart manufacturing of PE devices in the near future. We also provide a comparison with conventional quality control technologies or oﬀ-line measurements, such as four-point probe measurements, atomic force microscopy, optical microscopy, etc.

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Section: Eddy Current Testingmentioning

confidence: 99%

“…Lewis et al [104] used the eddy current approach for conductivity measurements. Figure 24(a) sketches the experimental setup used to measure the conductivity.…”

Section: Eddy Current Testingmentioning

confidence: 99%

Towards in-situ quality control of conductive printable electronics: a review of possible pathways

Zhuldybina¹,

Ropagnol²,

Blanchard³

2021

Flex. Print. Electron.

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“…The resulting functionality of these printed devices is highly dependent on the quality of the deposited ink. Nowadays, ink quality is mainly controlled based on defects [8][9][10] , including electrical properties 6,[11][12][13] surface morphology 11,[14][15][16] , and ink distribution, which induces dimensional distortions 8,17,18 , such as enlargement or shrinkage. To increase the electrical functionality of printed devices, it is critical to monitor the dimensional distortions 19 , which have been tested extensively [8][9][10] .…”

Section: Introductionmentioning

confidence: 99%

Printing accuracy tracking with 2D optical microscopy and super-resolution metamaterial-assisted 1D terahertz spectroscopy

et al. 2020

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Printable electronics is a promising manufacturing technology for the potential production of low-cost flexible electronic devices, ranging from displays to active wear. It is known that rapid printing of conductive ink on a flexible substrate is vulnerable to several sources of variation during the manufacturing process. However, this process is still not being subjected to a quality control method that is both non-invasive and in situ. To address this issue, we propose controlling the printing accuracy by monitoring the spatial distribution of the deposited ink using terahertz (THz) waves. The parameters studied are the printing speed of an industrial roll-toroll press with flexography printing units and the pre-calibration compression, or expansion factor, for a pattern printed on a flexible plastic substrate. The pattern, which is carefully selected, has Babinet's electromagnetic transmission properties in the THz frequency range. To validate our choice, we quantified the geometric variations of the printed pattern by visible microscopy and compared its accuracy using one-dimensional THz spectroscopy. Our study shows a remarkable agreement between visible microscopic observation of the printing performance and the signature of the THz transmission. Notably, under specific conditions, one-dimensional (1D) THz information from a resonant pattern can be more accurate than two-dimensional (2D) microscopy information. This result paves the way for a simple strategy for non-invasive and contactless in situ monitoring of printable electronics production.

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“…The current inline inspection methods available for the quality assurance of R2R processes include optical inspection with different approaches [7][8][9]. Other non-contact methods to evaluate the quality in the R2R process include inductive sensors for measuring sheet resistances [10], eddy current and capacitive sensors for the thickness measurement of printed conductive patterns [11] and thermography for a characterization of the conductive thin films [12].…”

Section: Introductionmentioning

confidence: 99%

Quality assurance for rotary screen printed wiring backplanes with automated roll-to-roll electrical test equipment

Happonen

Kokko

Juntunen

et al. 2019

Flex. Print. Electron.

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The roll-to-roll (R2R) printing process enables large-scale manufacturing of conductive wirings for the system integration of printed and hybrid electronics. As the number of R2R printed units in a run is typically high, a systematic approach is required to verify the outcome of manufacturing process extensively. This study presents a piece of automated R2R testing equipment, which is capable of the comprehensive electrical testing of printed and flexible electronics, and discusses the main findings provided by the test system in a use case of an R2R printed wiring backplane for a large-area display element. The automated R2R tester utilizes a bed-of-nails test method incorporated into the reeling equipment as a stop and go process. In this scheme, a bed-of-nails is a layout-specific test fixture providing physical contacts on the web. The actual measurement operations are performed by general-purpose electrical test equipment through standard industrial buses. Overall, the movement of the web containing printed electronics and the test operations for these are controlled by a test automation software. In this study, the R2R functional tester is utilized to evaluate the outcome of a rotary screen printing process for a large area backplane wiring of s 7×20 RGB LED matrix. The study presents the needed test cases for the full test coverage of printed wiring at an area of approximately 190 mm×405 mm in each backplane unit. As the roll length is over 150 meters, the testing process systematically produces over 100 000 resistance measurement results to evaluate the manufacturing process yield and process variations from an electrical perspective. The paper concludes the main test results, and discusses the usability of the developed testing system and the protocol in this use case application.

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High-speed non-contact sheet resistivity monitoring of printed electronics using inductive sensors

Cited by 6 publications

References 17 publications

Towards in-situ quality control of conductive printable electronics: a review of possible pathways

Towards in-situ quality control of conductive printable electronics: a review of possible pathways

Printing accuracy tracking with 2D optical microscopy and super-resolution metamaterial-assisted 1D terahertz spectroscopy

Quality assurance for rotary screen printed wiring backplanes with automated roll-to-roll electrical test equipment

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