32.1: <i>Invited Paper</i>: A Comparison of Pixel Circuits for Active Matrix Polymer/Organic LED Displays

Fish, D.; Young, N. D.; Childs, M. J.; Steer, W. A.; George, David J.; McCulloch, D.J.; Godfrey, Sandra; Trainer, M.; Johnson, Mark; Giraldo, A.; Lifka, H.; Hunter, I.

doi:10.1889/1.1830944

Cited by 26 publications

(21 citation statements)

References 3 publications

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“…[2][3][4][5][6][7][8][9][10][11][12][13] Among them, a time-ratio gray-scale method with a simple pixel circuit comprised of two transistors and a storage capacitor, is known to give excellent image uniformity. 14,15 In this method, a gray level is produced by turning the OLED in each pixel on or off during each of multiple subframe periods. [6][7][8][9]12 This approach can achieve a very high-resolution AMOLED display with more than 300 ppi because it requires a small number of TFT devices in each pixel and few global signal or power lines across a pixel.…”

Section: Introductionmentioning

confidence: 99%

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

et al. 2009

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Abstract— Early loss of image uniformity has been a critical drawback of active‐matrix organic light‐emitting‐diode (AMOLED) displays operated in time‐ratio gray‐scale mode. This problem is addressed with an analog calibration technique which measures the voltage across each OLED for a given current and subsequently controls the supply voltage of pixels and the voltage drop across the driving th in‐film transistor (TFT) of each OLED. The uniformity of test cells, which were aged to produce image sticking in a chessboard pattern, were improved. A measure of image sticking, called the extracted image‐sticking value (EISV), was formulated, which is developed and used for the quantitative evaluation of the calibration method. OLED voltages over a range of about 0.35 V were compensated to produce more uniform OLED currents than those before aging. The variation of luminance associated with image sticking was reduced by about 40% for a full‐white image after between 2 and 10 hours of accelerated aging with a constant voltage of 8 V across an OLED.

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Section: Introductionmentioning

confidence: 99%

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

et al. 2009

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“…11 Time-related electrical stress variations in both V t and mobility usually occur. 12,13 In contrast, in most a-Si processes, the initial V t and µ are uniform within a backplane. 10,14 While time-related electrical stress may produce large V t variations, there is typically little change in mobility.…”

Section: Introductionmentioning

confidence: 99%

V_tCompensated voltage‐data a‐Si TFT AMOLED pixel circuits

Sanford

Libsch

2004

J Soc Info Display

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Abstract— Active‐matrix organic light‐emitting‐diode (AMOLED) displays are now entering the marketplace. The use of a thin‐film‐transistor (TFT) active matrix allows OLED displays to be larger in size, higher in resolutions and lower in power dissipation than is possible using a conventional passive matrix. A number of TFT active‐matrix pixel circuits have been developed for luminance control, while correcting for initial and electrically stressed TFT parameter variations. Previous circuits and driving methods are reviewed. A new driving method is presented in which the threshold‐voltage (Vt) compensation performance, along with various circuit improvements for amorphous‐silicon (a‐Si) TFT pixel circuits using voltage data, are discussed. This new driving method along with various circuit improvements is demonstrated in a state‐of‐the‐art 20‐in. a‐Si TFT AMOLED HDTV.

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“…1,2 However, AMOLED suffers from the issue of uniformity owing to the mobility and threshold voltage variation in thin-film transistor (TFT). 3 To solve the uniformity issue, numerous pixel circuits to compensate the TFT variation were proposed. 4 However, this method of in-pixel compensation can significantly reduce the aperture ratio due to the additional TFTs and control buses, which problem is more severe in displays with high pixel density.…”

Section: Introductionmentioning

confidence: 99%

An external compensation method for AMOLED using the concept of ramp‐stop

Tai

Lin

2017

J Soc Info Display

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In this paper, we propose an external feedback method to compensate the device variation for active‐matrix organic light‐emitting diode. The pixel data current is controlled by ramping the gate voltage and converted to the sensed voltage Vsense in real time. When Vsense is equal to a preset voltage Vdata, the switching block outputs the low potential to stop the ramping. Therefore, the gate voltage is locked at the value corresponding to the target data current. This circuit is implemented with three thin‐film transistors in the active area and some functional blocks in driver integrated circuit (IC), namely, sentinel block, current‐voltage converting block, and switching block. Unlike the other usual methods of external compensation requiring double number of connections between driver IC and glass, by using the common ramping signal and a simple circuit made on glass, the proposed method can be implemented with only one pin per column.

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32.1: Invited Paper: A Comparison of Pixel Circuits for Active Matrix Polymer/Organic LED Displays

Abstract: In this paper measurements on several types of active matrix polymer LED (AMPLED) displays will be presented. The issues of image uniformity and polymer aging will be addressed by pixel circuit designs.

Cited by 26 publications

References 3 publications

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

V_tCompensated voltage‐data a‐Si TFT AMOLED pixel circuits

An external compensation method for AMOLED using the concept of ramp‐stop

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32.1: Invited Paper: A Comparison of Pixel Circuits for Active Matrix Polymer/Organic LED Displays

Abstract: In this paper measurements on several types of active matrix polymer LED (AMPLED) displays will be presented. The issues of image uniformity and polymer aging will be addressed by pixel circuit designs.

Cited by 26 publications

References 3 publications

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

Reducing image sticking in AMOLED displays with time‐ratio gray scale by analog calibration

VtCompensated voltage‐data a‐Si TFT AMOLED pixel circuits

An external compensation method for AMOLED using the concept of ramp‐stop

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Product

Resources

About

V_tCompensated voltage‐data a‐Si TFT AMOLED pixel circuits