44‐1: Photo Sensors Embedded within TFT‐LCD with Three Primary Colors Optical Touch Function

Kuo, Chia‐Wei; Hung, Ching-Lang; Liao, Yi-Yang; Tsai, Lo-Hsien; Tzeng, Bo-Shiang; Lu, Shao-Ping; Liu, Yu-Jung; Lin, Chin‐An; Chiang, Mao-Lun; Lin, Yan‐Cheng; Yu, Jian‐Shen

doi:10.1002/sdtp.12992

Cited by 5 publications

(2 citation statements)

References 8 publications

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“…Furthermore, high sensitivity to visible light of a-Si:H TFT is also widely applied in LCD applications to support backlighting, fingerprint sensing, X-ray image generation, and optical input functions for providing several valueadded functions [8]- [12]. Thus, the in-cell touch panel using optical sensors that are based on a-Si:H TFTs can perform multi-position sensing functions without any additional photolithographic mask or processing step in the fabrication and increasing the complexity of the position sensing algorithms [13], [14]. Unlike the mainstream capacitive touch panel, users can use the optical signal from a long distance to achieve contactless detection and innovate interactive applications.…”

Section: Introductionmentioning

confidence: 99%

Lifetime Optimization of Optical Sensing System With Highly Reliable a-Si:H TFT-Based Optical Sensor and Driver Circuit in Large AMLCDs

Lin,

Lee,

et al. 2024

IEEE Access

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This paper presents a long-lifetime optical sensing system that integrates optical sensors and driver circuits that use hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) to realize binary detection of optical signal with a multi-position sensing function for use in large active-matrix liquid crystal display (AMLCD). The optical sensor suppresses the effect of variations in ambient white light using a white-light photocurrent gating (WPCG) structure and increases the reliability of two photo TFTs by halving the drain-to-source voltage (VDS) stress. The driver circuit switches two driving TFTs between their two modes to recover the threshold voltage (VTH) shifts during a long sensing period or generate an output waveform with a large pulse width for driving the optical sensor. Experimental results indicate that the degradation of the photocurrent of the photo TFT is suppressed from 3.71 nA to 1.03 nA, representing an improvement of 72.2% relative to the original WPCG structure. The minimum difference between the output voltages of the optical sensing systems with and without an optical signal under illumination by ambient white light from 500 to 10000 lux is 18.58 V. According to an accelerated lifetime test, the feasibility of using the optical sensing system in large AMLCDs is verified.

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Section: Introductionmentioning

confidence: 99%

Lifetime Optimization of Optical Sensing System With Highly Reliable a-Si:H TFT-Based Optical Sensor and Driver Circuit in Large AMLCDs

Lin,

Lee,

et al. 2024

IEEE Access

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“…Unlike infrared or projected capacitive (Pcap) touch panels, TFT-based optical sensors can be directly fabricated on a glass substrate, realising a compact product without additional sensing modules [5][6][7][8][9]. Since hydrogenated amorphous silicon (a-Si:H) TFTs have good optical responses to visible light and have a uniform structure on large substrates, several optical sensors that are based on a-Si:H TFTs have been proposed for integration into LCDs and to support an optical input function and remote control for multiuser applications [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Optical properties of a‐Si:H thin‐film transistors by illumination by white light with different colour temperatures

Chang

Lee

Chen

et al. 2022

IET Circuits, Devices & Syst

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This work investigates the optical properties of hydrogenated amorphous silicon thin-film transistors (a-Si:H TFTs) using the transmittances of colour filters and the spectra of commercialised white light-emitting diodes (LEDs). The ratios of the measured photocurrents obtained using the TFTs that are covered and are not covered colour filters are related to the effective illumination from white LEDs with different colour temperatures that pass through the colour filters. A new factor that is based on these ratios of photocurrents is proposed to evaluate the output characteristics of optical sensors with our previously developed white-light photocurrent gating (WPCG) structure. The analytical results demonstrate that the proposed factor and the output voltages of the WPCG structure are highly correlated with each other, favouring the optimisation of the design parameters to realise an optical sensor that is highly reliable under diverse conditions for use in large interactive displays.

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P‐14: Student Poster: Optical Sensor with New Driving Method Using Amorphous Silicon Thin‐Film Transistors to Increase Three Types of Sensed Light for Large Interactive Displays

Lee

Liu

Kuo

et al. 2021

Symp Digest of Tech Papers

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44‐1: Photo Sensors Embedded within TFT‐LCD with Three Primary Colors Optical Touch Function

Cited by 5 publications

References 8 publications

Lifetime Optimization of Optical Sensing System With Highly Reliable a-Si:H TFT-Based Optical Sensor and Driver Circuit in Large AMLCDs

Lifetime Optimization of Optical Sensing System With Highly Reliable a-Si:H TFT-Based Optical Sensor and Driver Circuit in Large AMLCDs

Optical properties of a‐Si:H thin‐film transistors by illumination by white light with different colour temperatures

P‐14: Student Poster: Optical Sensor with New Driving Method Using Amorphous Silicon Thin‐Film Transistors to Increase Three Types of Sensed Light for Large Interactive Displays

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