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The display device has a significant contribution to the total power, which is critical for mobile consumer-electronic devices due to a limited battery capacity. We develop a power model of the active-matrix organic light-emitting diode (AMOLED) display and analyze the power contribution of thin-film transistor (TFT), OLED, and VDD line drop. Both theoretical analysis and calculation are derived from TFT mobility, OLED luminous efficiency, pixel aperture ratio, and VDD line drop. The TFT mobility from 0.1 to 10\; \textcm^2/(\textV\cdot \texts) is a bottleneck of display power. Metal oxide TFT may be more suitable for AMOLED display since relatively high mobility and low fabrication temperature. High luminous efficiency of OLED and top emission structure can decrease power consumption abundantly. The impact of copper wire technology is also discussed in large-size panels. [ABSTRACT FROM PUBLISHER]

An analytical expression for density of trap states (DOS) related to the surface potential is derived from the Poisson's equation and the surface potential corresponding to certain gate–source voltage is obtained by integrating the low-frequency capacitance–voltage characteristic. It is shown that the DOS for indium–zinc–oxide thin-film transistors (IZO TFTs) may be represented by the superposition of exponential deep states and exponential tail states with the density of deep/tail states ( $N_{{\rm DA}}/N_{{\rm TA}}$) at the conduction edge as 1.2 × 1017 cm−3·eV−1/9.0 × 1017 cm−3 ·eV−1 and the characteristics energy of deep/tail states ( $E_{{\rm DA}}/E_{{\rm TA}}$) as 5.0 eV/0.182 eV. These extracted parameters are further verified by the comparison of the measured transfer and output characteristics of IZO TFTs with the simulation results by a 2D device simulator ATLAS (Silvaco). Hence, this extraction method of DOS may be very useful for characterizing metal oxide TFTs since it is analytical, fast, and accurate. [ABSTRACT FROM PUBLISHER]

This paper presents a novel compensation pixel circuit for active-matrix organic light-emitting diode displays, in which the coupling effect mask technology is developed to compensate the threshold voltage of driving thin-film transistor whether it is positive or negative. Twenty discrete compensation pixel circuits have been fabricated by In-Zn-O thin-film transistors process. It is measured that the non-uniformity of the proposed pixel circuit is significantly reduced with an average value of 8.6%. Furthermore, the organic light-emitting diode emission current remains constant during 6 h continuous operation, which also confirms the validity of the proposed pixel circuit. [ABSTRACT FROM AUTHOR]

This letter presents a high-speed, voltage-programmed pixel circuit for active-matrix organic light-emitting diode displays employing threshold voltage one-time detection method. The proposed pixel circuit that consists of one driving thin-film transistor (TFT), four switching TFTs, two capacitors, and four control signal lines can effectively compensate for the threshold voltage shift of the driving TFT and the OLED degradation. The threshold voltage of one-time detection method is realized by an ingenious application of capacitor coupling effect, and it is well-verified by comparing it with the conventional driving scheme. In this method, data is directly renewed without the periods of initialization and threshold voltage detection from the second-frame beginning. Moreover, this method can also be applied to other compensation pixel circuits. [ABSTRACT FROM PUBLISHER]