A Review of Fingerprint Sensors: Mechanism, Characteristics, and Applications

Yu, Yonghong; Niu, Qiming; Li, X. Rong; Xue, Jianshe; Liu, Weiguo; Lin, Dabin

doi:10.3390/mi14061253

Cited by 14 publications

(2 citation statements)

References 250 publications

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“…The piezoelectric arrays were developed in this work using La/Sm-doped PMN-PZT ceramic films as a piezoelectric layer and PDMS as a flexible countersink [ 35 ]. The fabrication process is presented in Figure 1 b.…”

Section: Methodsmentioning

confidence: 99%

A Highly Flexible Piezoelectric Ultrasonic Sensor for Wearable Bone Density Testing

Song,

Wang,

Zhang

et al. 2023

Micromachines

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Driven by the loss of bone calcium, the elderly are prone to osteoporosis, and regular routine checks on bone status are necessary, which mainly rely on bone testing equipment. Therefore, wearable real-time healthcare devices have become a research hotspot. Herein, we designed a high-performance flexible ultrasonic bone testing system using axial transmission technology based on quantitative ultrasound theory. First, a new rare-earth-element-doped PMN-PZT piezoelectric ceramic was synthesized using a solid-state reaction, and characterized by X-ray diffraction and SEM. Both a high piezoelectric coefficient d33 = 525 pC/N and electromechanical coupling factors of k33 = 0.77, kt = 0.58 and kp = 0.63 were achieved in 1%La/Sm-doped 0.17 PMN-0.47 PZ-0.36 PT ceramics. Combining a flexible PDMS substrate with an ultrasonic array, a flexible hardware circuit was designed which includes a pulse excitation module, ultrasound array module, amplification module, filter module, digital-to-analog conversion module and wireless transmission module, showing high power transfer efficiency and power intensity with values of 35% and 55.4 mW/cm2, respectively. Finally, the humerus, femur and fibula were examined by the flexible device attached to the skin, and the bone condition was displayed in real time on the mobile client, which indicates the potential clinical application of this device in the field of wearable healthcare.

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Section: Methodsmentioning

confidence: 99%

A Highly Flexible Piezoelectric Ultrasonic Sensor for Wearable Bone Density Testing

Song,

Wang,

Zhang

et al. 2023

Micromachines

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“…Its reliability is underscored by the persistence of fingerprints over time, as evidenced by studies such as Monson et al [1] and Yoon et al [2]. Coupled with its high accuracy and cost-effectiveness [3], fingerprint recognition stands as a dependable biometric identifier.…”

Section: Introductionmentioning

confidence: 99%

Toward Synthetic Physical Fingerprint Targets

Ruzicka,

Strobl,

Bergmann

et al. 2024

Sensors

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Biometric fingerprint identification hinges on the reliability of its sensors; however, calibrating and standardizing these sensors poses significant challenges, particularly in regards to repeatability and data diversity. To tackle these issues, we propose methodologies for fabricating synthetic 3D fingerprint targets, or phantoms, that closely emulate real human fingerprints. These phantoms enable the precise evaluation and validation of fingerprint sensors under controlled and repeatable conditions. Our research employs laser engraving, 3D printing, and CNC machining techniques, utilizing different materials. We assess the phantoms’ fidelity to synthetic fingerprint patterns, intra-class variability, and interoperability across different manufacturing methods. The findings demonstrate that a combination of laser engraving or CNC machining with silicone casting produces finger-like phantoms with high accuracy and consistency for rolled fingerprint recordings. For slap recordings, direct laser engraving of flat silicone targets excels, and in the contactless fingerprint sensor setting, 3D printing and silicone filling provide the most favorable attributes. Our work enables a comprehensive, method-independent comparison of various fabrication methodologies, offering a unique perspective on the strengths and weaknesses of each approach. This facilitates a broader understanding of fingerprint recognition system validation and performance assessment.

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Molecular Engineering of Benzobisoxazole‐Based Conjugated Polymers for High‐Performance Organic Photodetectors and Fingerprint Image Sensors

Shin,

Jeong,

Darici Lee

et al. 2024

Energy & Environ Materials

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Various novel conjugated polymers (CPs) have been developed for organic photodetectors (OPDs), but their application to practical image sensors such as X‐ray, R/G/B, and fingerprint sensors is rare. In this article, we report the entire process from the synthesis and molecular engineering of novel CPs to the development of OPDs and fingerprint image sensors. We synthesized six benzo[1,2‐d:4,5‐d']bis(oxazole) (BBO)‐based CPs by modifying the alkyl side chains of the CPs. Several relationships between the molecular structure and the OPD performance were revealed, and increasing the number of linear octyl side chains on the conjugated backbone was the best way to improve Jph and reduce Jd in the OPDs. The optimized CP demonstrated promising OPD performance with a responsivity (R) of 0.22 A/W, specific detectivity (D*) of 1.05 × 1013 Jones at a bias of −1 V, rising/falling response time of 2.9/6.9 μs, and cut‐off frequency (f‐3dB) of 134 kHz under collimated 530 nm LED irradiation. Finally, a fingerprint image sensor was fabricated by stacking the POTB1‐based OPD layer on the organic thin‐film transistors (318 ppi). The image contrast caused by the valleys and ridges in the fingerprints was obtained as a digital signal.

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A Review of Fingerprint Sensors: Mechanism, Characteristics, and Applications

Cited by 14 publications

References 250 publications

A Highly Flexible Piezoelectric Ultrasonic Sensor for Wearable Bone Density Testing

A Highly Flexible Piezoelectric Ultrasonic Sensor for Wearable Bone Density Testing

Toward Synthetic Physical Fingerprint Targets

Molecular Engineering of Benzobisoxazole‐Based Conjugated Polymers for High‐Performance Organic Photodetectors and Fingerprint Image Sensors

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