Steven A. Van Slyke

4.2: Design ofanlmproved Pixel fora Polysilicon Active‐Matrix Organic LED Display

A polysilicon transistor based active matrix organic light emitting diode (AMOLED) pixel with high pixel to pixel luminance uniformity is reported. The new pixel powers the OLEDS with small constant currents to ensure consistent brightness and extended life. Excellent pixel to pixel current drive uniformity is obtained despite the threshold voltage variation inherent in polysilicon transistors. considerations in the design for high information content displays are discussed.

System considerations for RGBW OLED displays

Abstract— The fabrication of full-color RGBW OLED displays using a white emitter with RGB color filters has been previously described. This paper discusses the effect of several display-system factors on the important RGBW OLED display performance attributes of power consumption, lifetime, and perceived image quality. These display-system factors include the spectrum of the white OLED, the white OLED structure, the color-filter selection, the subpixel aperture ratios, and the pixel arrangement (including sub-sampling).

A Polysilicon Active Matrix Organic Light Emitting Diode Display with Integrated Drivers

The design of an active matrix organic light emitting diode (AMOLED) display using a polysilicon thin film transistor pixel is described. Characteristics of the OLED response in the low current regime are described and their impact on the design of integrated driver circuitry is discussed. Integrated data and select scanners which generate the signals necessary for data capture and pixel calibration are presented.

27.2: Linear Source Deposition of Organic Layers for Full-Color OLED

A key requirement for fabrication of organic light emitting diode (OLED) displays is uniform film deposition over large areas because of the sensitivity of emission color and efficiency on film thickness. Conventional deposition using point sources is unattractive because of the requirement of a large source to substrate separation, usually with substrate rotation, to achieve acceptable thin film uniformity. By translating a novel extended linear evaporation source in a single direction, film non-uniformity of less than 5% has been demonstrated over a 300 mm × 400 mm substrate with a source to substrate separation of 100 mm. OLEDs with all organic layers deposited using linear sources have been determined to operate identically to devices fabricated using conventional point sources. The performance of doped and undoped devices as well as the advantages of linear source deposition over conventional deposition techniques will be described.

4.3: Lifetime- and Power-Enhanced RGBW Displays Based on White OLEDs

In this paper, we describe techniques for improving the power consumption and lifetime of full-color AMOLED displays with an RGBW pixel format. A highly efficient and stable white OLED, with color optimized for the display white point (D65) has been developed, which enables low power consumption as well as stable emission. Additionally, a novel approach for improving the lifetime of RGBW displays using subsampled R and B subpixels is discussed.

Performance enhancement of top- and bottom-emitting organic light-emitting devices using microcavity structures

In order to improve the efficiency of top- and bottom-emitting devices, metallic electrodes have been used to create microcavity effects within the OLED structure. Semi-transparent Ag is used as the anode in bottom-emitting microcavity structures, whereas various reflective opaque metallic anodes are used for the top emitters. The cathode used in both configurations is MgAg - thick and opaque in the case of the bottom emitter and thin and semi-transparent in the case of the top emitter. Modeling and experiments show that for the top-emitting structures, the device efficiency is roughly proportional to the reflectivity of the anode in the low reflectivity range and increases significantly more than predicted by reflectivity alone in the high-reflectivity range. An ultrathin CF x or MoO x hole-injecting layer allows for the use of many metals as anodes and is an important feature of the device structure. With an Ag anode, both the top- and bottom-emitting microcavity devices are about twice as efficient (on axis) as the analogous nonmicrocavity bottom-emitting device. Microcavity devices employing a C545T-doped Alq emitter exhibit efficiencies of 21 cd/A at 6.4 V and 20 mA/cm 2 , with operational stability equivalent to conventional bottom-emitting structures.

System design for a wide‐color‐gamut TV‐sized AMOLED display

Abstract— By using current technology, it is possible to design and fabricate performance-competitive TV-sized AMOLED displays. In this paper, the system design considerations are described that lead to the selection of the device architecture (including a stacked white OLED-emitting unit), the backplane technology [an amorphous Si (a-Si) backplane with compensation for TFT degradation], and module design (for long life and low cost). The resulting AMOLED displays will meet performance and lifetime requirements, and will be manufacturing cost-competitive for TV applications. A high-performance 14-in. AMOLED display was fabricated by using an in-line OLED deposition machine to demonstrate some of these approaches. The chosen OLED technologies are scalable to larger glass substrate sizes compatible with existing a-Si backplane fabs.

30.3: White Fluorescent PIN OLED with High Efficiency and Lifetime for Display Applications

Highly efficient and stable white PIN OLED structures based on Kodaks proprietary emitters and Novaleds proprietary p- and n-type dopants have been developed with a focus on AMOLED display applications. At color coordinates of 0.33/0.36, a current efficiency of 15.1 cd/A at a voltage of 3.0 V was achieved at 1000 cd/m2 brightness. The lifetime of this device is 27,000 hours at a starting luminance of 1000 cd/m2. The spectrum of the devices contains a contribution from four emitters (RGBY) and the emission of the presented OLED structures is therefore ideally suited for use in RGBW AMOLED displays. with variations of the blocking layers, the device efficiency can be increased to 16.8 cd/A, which corresponds to an external quantum efficiency of 7.3%. The results in this paper are based on a joint research effort between Eastman Kodak Company and Novaled.

35.3: High‐Performance Tandem White OLEDs Using a Li‐Free “P‐N” Connector

A nonmetallic connector has been developed for high-efficiency tandem white architecture. Forming the “N” type layer using NDN-26 doped into NET-18 and inserting an organometallic thin layer between the “N” and “P” layers results in a high-performance connector. An efficiency of 33 cd/A has been achieved at 6.7 V, 1000 cd/m2 and 10000K color temperature in a fluorescent based tandem emitter. This >15% EQE device also demonstrates a half-life of ∼80,000 h at 1000 cd/m2.

3.2: Digital Drive with White OLEDs

2T1C digital drive has been investigated with stable white OLEDs. A 2.5″ QVGA digital drive AMOLED prototype exhibited quite stable lifetime under constant voltage stress. The lifetime (T50) of an OLED device with 40% aperture ratio was over 5,000 h at an initial condition of 442 cd/m2 while the T50 at an initial condition of 175 cd/m2 is estimated to be over 20,000 h even under constant voltage stress. Motion artifacts are also improved with an automatic refresh rate conversion with less impact on power consumption.