39‐2: Highly Sensitive a‐Si:H PIN Photodiode Gated LTPS TFT for Optical In‐Display Fingerprint Identification

Zhou, Xianda; Zhang, Meng; Xu, Yitong; Zhou, Wei; Wang, Kai; Nathan, Arokia; Wong, Man; Kwok, Hoi Sing; Ou, Hai; Deng, Shaozhi; Xu, Ning

doi:10.1002/sdtp.12608

Cited by 5 publications

(3 citation statements)

References 10 publications

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“…Fingerprint sensor arrays ( Figure 5.1) [13] are becoming a mainstream security mechanism for mobile devices and are today available as autonomous silicon-based component. The integration of the fingerprint sensor array together with AMOLED displays [14][15][16] would benefit the footprint of the mobile device and the functionality, enabling detection of multiple fingers at once or even a palmprint.…”

Section: Adding a Fourth Pixel For Finger/palmprint Sensingmentioning

confidence: 99%

AMOLED Displays with In-Pixel Photodetector

Παπαδόπουλος¹,

Malinowski²,

Verschueren³

et al. 2020

Liquid Crystals and Display Technology

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The focus of this chapter is to consider additional functionalities beyond the regular display function of an active matrix organic light-emitting diode (AMOLED) display. We will discuss how to improve the resolution of the array with OLED lithography pushing to AR/VR standards. Also, the chapter will give an insight into pixel design and layout with a strong focus on high resolution, enabling open areas in pixels for additional functionalities. An example of such additional functionalities would be to include a photodetector in pixel, requiring the need to include in-panel TFT readout at the peripherals of the full-display sensor array for applications such as finger and palmprint sensing.

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Section: Adding a Fourth Pixel For Finger/palmprint Sensingmentioning

confidence: 99%

AMOLED Displays with In-Pixel Photodetector

Παπαδόπουλος¹,

Malinowski²,

Verschueren³

et al. 2020

Liquid Crystals and Display Technology

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“…4 photomasks are used for the fabrication of IGZO TFT and 2 fine-metal masks are for the perovskite photodiode fabrication. For comparison, 12 masks are required for typical conventional optical sensor fabrication [5,6].…”

Section: Introductionmentioning

confidence: 99%

Pixellated Perovskite Photodiode on IGZO Thin Film Transistor Backplane for Low Dose Indirect X-Ray Detection

Zou

Ben

et al. 2021

IEEE J. Electron Devices Soc.

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The integration of perovskite photodetectors with thin-film transistor (TFT) backplane or complementary metaloxide-semiconductor CMOS circuit is a key step towards prototyping perovskite-based image sensors. Here, we demonstrate a pixel configuration for indirect X-ray detection comprising of IGZO TFTs and perovskite photodiodes (PDs). The perovskite photodiode is patterned by a two-step deposition method. Our integrated TFT/PD pixel shows a weak light detection capability down to 4 nW cm-2 , and a fast-transient response to the pulse light and gate switching. Combining with a CsI scintillator, the integrated pixel achieves a specific X-ray sensitivity of 8.2  10 2 μC mGyair-1 cm-3. Theoretically, with a stateof-the-art scintillator, the new pixel can provide a detectable signal for X-ray imaging at a dose rate as low as 10 μGyair s-1. This work provides an advanced pixel design for high resolution, high sensitivity, and high frame-rate flat-panel imager.

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“…However, the most convenient and intuitive location of the fingerprint sensor is on the front face. Various types of sensors that can recognize fingerprints on display screens have been developed [1][2][3][4][5][6][7][8][9][10][11] . Typical examples include capacitive, optical, and ultrasonic fingerprint sensors.…”

Section: Introductionmentioning

confidence: 99%

On-screen fingerprint sensor with optically and electrically tailored transparent electrode patterns for use on high-resolution mobile displays

et al. 2020

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In this study, a mutual capacitive-type on-screen fingerprint sensor, which can recognize fingerprints on a display screen to provide smartphones with full-screen displays with a minimal bezel area, is fabricated. On-screen fingerprint sensors are fabricated using an indium tin oxide transparent conductor with a sheet resistance of ~10 Ω/sq. and a transmittance of ~94% (~86% with the substrate effect) in the visible wavelength range, and assembled onto a display panel. Even at this high transmittance, the electrodes can degrade the display quality when they are placed on the display. The interference between periodic display pixel arrays and sensor patterns can lead to the Moiré phenomenon. It is necessary to find an appropriate sensor pattern that minimizes the Moiré pattern, while maintaining the signal sensitivity. To search for appropriate patterns, a numerical calculation is carried out over wide ranges of pitches and rotation angles. The range is narrowed for an experimental evaluation, which is used to finally determine the sensor design. As the selected sensor pitches are too small to detect capacitance variations, three unit patterns are electrically connected to obtain a unit block generating a larger signal. By applying the selected sensor pattern and circuit driving by block, fingerprint sensing on a display is demonstrated with a prototype built on a commercial smartphone.

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39‐2: Highly Sensitive a‐Si:H PIN Photodiode Gated LTPS TFT for Optical In‐Display Fingerprint Identification

Abstract: A hybrid optical sensor that is merged with the display driving, low-temperature polysilicon thin-film transistor (TFT) is reported. The sensor achieves a fill factor >70% and a photoconductive gain > 10 3 %, which provides a promising solution for in-display fingerprint identification.

Cited by 5 publications

References 10 publications

AMOLED Displays with In-Pixel Photodetector

AMOLED Displays with In-Pixel Photodetector

Pixellated Perovskite Photodiode on IGZO Thin Film Transistor Backplane for Low Dose Indirect X-Ray Detection

On-screen fingerprint sensor with optically and electrically tailored transparent electrode patterns for use on high-resolution mobile displays

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