P‐31: Pixel Circuit with Backgate Feedback for Deep and Rich Black Expressions on Light‐Emitting Display

Nishiyama, Tomohiro; Tanaka, Kohei; Yamamoto, Kaoru; Yamamoto, Keiichi; Uchida, Seiichi; Yonebayashi, Ryo; Miyamoto, Tomofumi; Hosokawa, Mari; Katoh, Hiromi

doi:10.1002/sdtp.13180

Cited by 6 publications

(4 citation statements)

References 7 publications

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“…It has been reported that this problem can be solved by improving the circuit design. [1] However, in order to change the circuit design, wirings and layers are added, so that there is a concern that the circuit is complicated.…”

Section: Introductionmentioning

confidence: 99%

P‐13: Large Subthreshold Swing of LTPS TFTs by Efficient Annealing Method for Light Emitting Diode Displays

Saito¹,

Kanzaki²,

Miwa³

et al. 2020

Symp Digest of Tech Papers

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Section: Introductionmentioning

confidence: 99%

P‐13: Large Subthreshold Swing of LTPS TFTs by Efficient Annealing Method for Light Emitting Diode Displays

Saito¹,

Kanzaki²,

Miwa³

et al. 2020

Symp Digest of Tech Papers

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“…It is interesting that the SS optimization direction of LED is different from that of OLED due to the difference in LED driving method. The high SS is desirable for OLED pixel circuits which modulate the amplitude of subthreshold current to precisely express low gray levels [26], [27], whereas the low SS is advantageous for LED pixel circuits which modulate the width of emission time for the same operation.…”

Section: Simulation and Discussionmentioning

confidence: 99%

A Compact Amorphous In-Ga-Zn-Oxide Thin Film Transistor Pixel Circuit With Two Capacitors for Active Matrix Micro Light-Emitting Diode Displays

Kang

Park

Kang

et al. 2023

IEEE J. Electron Devices Soc.

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In this paper, we propose a novel amorphous In-Ga-Zn-oxide (a-IGZO) thin film transistor (TFT) pixel circuit for pulse width modulation (PWM) driving active matrix micro light-emitting diode (LED) displays. The proposed pixel circuit compensates for wavelength shifts according to gray level and threshold voltage (VTH) variation of TFTs with only two capacitors. This compact operation can be achieved by simultaneous compensation for VTH along with data input in the constant current generation (CCG) circuit and the PWM circuit, which consist the pixel. Since the VTH variation in TFTs is compensated, the proposed pixel circuit can supply a uniform and stable current to the LED throughout all gray levels. The compensation accuracy was verified by HSPICE with an oxide TFT model based on the measurement data.In addition, we analyzed the optimization method to improve the PWM driving by controlling the electrical properties of TFT, and verified this approach by simulation.

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“…the utilization of a broader data range for expressing low gray levels. Considering that conventional OLED displays tried to expand the data range for low gray levels in order to achieve deep and rich black expression [23], [24], the proposed pixel circuit is expected to offer significant advantages for the precise expression of low gray levels. Fig.…”

Section: Ccg Part Compensationmentioning

confidence: 99%

A New PWM Operational Scheme for MicroLED Displays Using Inverter and Dynamic SWEEP Signal Slope for Low Gray Level Expression

Kang,

Park,

Park

et al. 2023

IEEE Access

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In this paper, we present a novel pulse width modulation (PWM) operational scheme for micro-light-emitting-diode (μLED) displays using inverter and dynamic SWEEP signal slope. In the proposed PWM operational scheme, the slope of the SWEEP signal steepens as the gray level decreases. This adjustable SWEEP signal slope further shortens the falling time compared to the inverter-only strategy, leading to an exceptional capability to express extremely low gray levels. We implement the proposed scheme with low-temperature poly-Si oxide (LTPO) thin-film transistor (TFT) pixel circuit, and verify the operation through HSPICE based on measured TFT data. The simulation results show that the proposed scheme can significantly shorten the falling time to under 1 μs level. The gray level of 14 G is accurately expressed without wavelength shift or pulse distortion, achieving a falling time of 0.21 μs. In addition, we also verify the compensation accuracy of the pixel circuit, and the results indicate that the proposed pixel circuit can reliably compensate for TFT variations.

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P‐31: Pixel Circuit with Backgate Feedback for Deep and Rich Black Expressions on Light‐Emitting Display

Cited by 6 publications

References 7 publications

P‐13: Large Subthreshold Swing of LTPS TFTs by Efficient Annealing Method for Light Emitting Diode Displays

P‐13: Large Subthreshold Swing of LTPS TFTs by Efficient Annealing Method for Light Emitting Diode Displays

A Compact Amorphous In-Ga-Zn-Oxide Thin Film Transistor Pixel Circuit With Two Capacitors for Active Matrix Micro Light-Emitting Diode Displays

A New PWM Operational Scheme for MicroLED Displays Using Inverter and Dynamic SWEEP Signal Slope for Low Gray Level Expression

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