36.1: 6‐Bit Digital VGA OLED

Mizukami, Mayumi; Inukai, Kazutaka; Yamagata, Hirokazu; Konuma, Toshimitsu; Nishi, Takeshi; Koyama, Jun; Yamazaki, S.; Tsutsui, Tetsuo

doi:10.1889/1.1833103

Cited by 63 publications

(42 citation statements)

References 8 publications

(5 reference statements)

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“…In fact, similar frequency dependent JOLED-VOLED shifts were also observed for other multi-layer red and green OLEDs in our previous study [20]. Therefore, we believe that high frequency operation would give a benefit to lifetime improvement in AMOLED with a conventional digital driving scheme, where one frame time is divided into several sub-frames according to the number of bits representing gray scales [2]. A sub-frame representing the most significant bit (MSB) can be considered to approximately occupy half of one frame time.…”

Section: Resultssupporting

confidence: 82%

“…Recently, digital driving methods have attracted much attention for simplifying pixel structures of active-matrix organic light-emitting diode (OLED) displays (AMOLEDs) [1][2][3][4] in comparison with analog counterparts [5][6]. However, in digital driving methods, a driving thin-film transistor (TFT) is generally operated in the linear regime, making pixel brightness degradation more sensitive to a shift in current density-voltage (J OLED -V OLED ) characteristics of pixel OLEDs.…”

Section: Introductionmentioning

confidence: 99%

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Frequency Dependency of Multi-layer OLED Current Density-voltage Shift and Its Application to Digitally-driven AMOLED

Kim¹,

Kim²,

Hong³

2012

Journal of the Optical Society of Korea

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We report, for the first time, operation frequency dependence of current density-voltage (JOLED-VOLED) shift for multi-layer organic light-emitting diodes (OLEDs). When the OLEDs were electrically stressed for 21 hours with 50% duty voltage pulses at 60, 120, 240, and 360 Hz, the JOLED-VOLED shifts were suppressed by half for 360 Hz operation compared with 60 Hz operation, but with little change in emission efficiencies. This frequency dependent JOLED-VOLED shift is believed to be commonly observed for typical multi-layer OLEDs and can be used to further improve lifetime of digitally-driven active-matrix OLED displays.

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Section: Resultssupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Frequency Dependency of Multi-layer OLED Current Density-voltage Shift and Its Application to Digitally-driven AMOLED

Kim¹,

Kim²,

Hong³

2012

Journal of the Optical Society of Korea

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“…The conventional analog driving techniques require complicated pixel structure for V T -shift compensation [1]. Digital driving technique is proposed as an alternative since it can mitigate V T -shift issue using a simple 2-TFT-1-Cap pixel structure [2]. False image contour is the common drawback of the conventional PWM-based digital driving technique [3].…”

Section: Descriptionmentioning

confidence: 99%

A digital driving technique for an 8-bit QVGA AMOLED using delta-sigma modulation

Jang

Kwon

Tjandranegara

et al. 2009

2009 IEEE International Symposium on Circuits and Systems

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“…To reduce the variation in pixel luminance, a compensation circuit is included in each pixel; however, this reduces the resolution and yield of AMOLED panels. Digital driving for AMOLED displays [4], [5] has been researched to enhance the immunity to the variation in the electrical characteristics of TFTs because it uses driving TFT as a switch rather than a current source. Thus, digital driving has several advantages such as high resolution and high image uniformity due to its simple structure and high immunity to the variation of Manuscript TFT characteristics.…”

Section: Introductionmentioning

confidence: 99%

Lifetime Extension Method for Active Matrix Organic Light-Emitting Diode Displays Using a Modified Stretched Exponential Decay Model

Hong

Kwon

2015

IEEE Electron Device Lett.

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In this letter, we propose a compensation method for organic light-emitting diode (OLED) degradation occurring in a digital driving scheme for active-matrix OLED displays. The proposed method, in which we are the first to propose, employs the modified stretched exponential decay (SED) model to characterize the OLED degradation and compensates for the associated luminance decrease; the lifetime of an OLED panel can thereby be extended. The OLED panel is fabricated using low-temperature poly-Si thin-film transistors, and measured to verify the modified SED model and the proposed compensation method. The measurement results show that the luminance degradation with and without the proposed method is 0.3% and 6%, 4% and 17.8%, and 7.4% and 30.4%, for red, green, and blue OLEDs, respectively. This measurement is taken after 40 h of operation under a 350 cd/m 2 initial luminance. Accordingly, the proposed compensation method extends the lifetime of the OLED panel up to 72.5, 15.5, and 20.75 times longer in red, green, and blue OLEDs, respectively, compared with the conventional method. IndexTerms-OLED degradation, digital driving, compensation, AMOLED, stretched exponential decay model, lifetime extension of AMOLED.

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36.1: 6‐Bit Digital VGA OLED

Abstract: We developed 0.7 inch VGA TFT-OLED with a 64 gray-scale integrated driver circuit. The TFT-OLED has good image uniformity due to digital operation. Control in a time-ratio was useful for achieving large gray-scale level. Our simplified pixel configuration accomplished high resolution.

Cited by 63 publications

References 8 publications

Frequency Dependency of Multi-layer OLED Current Density-voltage Shift and Its Application to Digitally-driven AMOLED

Frequency Dependency of Multi-layer OLED Current Density-voltage Shift and Its Application to Digitally-driven AMOLED

A digital driving technique for an 8-bit QVGA AMOLED using delta-sigma modulation

Lifetime Extension Method for Active Matrix Organic Light-Emitting Diode Displays Using a Modified Stretched Exponential Decay Model

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