John W. Hamer

Stable RGBW AMOLED display with OLED degradation compensation using electrical feedback

The active matrix organic light emitting diode (AMOLED) display is a strong candidate for the next generation display because of attributes such as low power consumption, wide viewing angle, highly saturated colors, fast response, and high contrast ratio. More importantly, its structural simplicity (compared to the active matrix liquid crystal display) gives it the potential for low fabrication costs. Since the OLED is a current driven device, an active matrix of thin film transistors (TFTs) is needed to provide a programmable current source at each pixel [1]. Thus, OLED luminance becomes extremely sensitive to the temporal instability and spatial non-uniformity of the TFTs which can result in Mura, image sticking, and reduced lifetime [1–4].

Stoichiometric interpretation of multireaction data: Application to fed-batch fermentation data

Abstract A methodology has been developed that allows meaningful interpretation of multicomponent reaction data in terms of a few simple “reactions” with time-invariant stoichiometry. This is particularly helpful when applied to fermentation data, since the complexity of the reaction network in many cases defies exact biochemical treatment, and existing techniques, which represent data using equations with time-varying stoichiometry, are difficult to interpret. The reactions that are selected explain the macroscopic compositional changes observed in the broth and exit streams, and incorporate a priori ideas about the irreversibility of particular metabolic pathways. Once these simple reactions are selected, the associated reaction rates are also known as functions of time, without any need for additional kinetic information. These rates can then be used to search for environmental explanations for the observed behavior. With insight as to the pathways that might be independently manipulated, and ideas as to the effect of environmental factors on the velocity in each path, one can move towards yield and productivity objectives. Three examples of fermentations for primary metabolites are shown.

Transfer-Printed Microscale Integrated Circuits for High Performance Display Backplanes

Active-matrix organic light-emitting diode displays have been fabricated using backplanes with transfer-printed microscale silicon integrated circuits (ICs) in place of conventional thin-film transistors. The ICs were fabricated using a commercially available semiconductor foundry process, and the wafers were subsequently processed to prepare the ICs for transfer-printing. The microscale ICs were transfer printed onto glass substrates and interconnected using a single-level, thin-film metallization process. The resulting OLED display exhibited good pixel-to-pixel luminance uniformity, high luminance, excellent controllability and high switching speed. The transfer-printing process achieved good positional accuracy and high yield.

69.4: Invited Paper: Mass Production of Full-Color AMOLED Displays

Mass production of full-color active-matrix OLED (AMOLED) displays began in October 2002 at SK Display Corporation. This milestone was achieved through an integration of modified low-temperature polysilicon substrates (LTPS), manufacturing subsystems for the uniform deposition of OLED device structures, encapsulation subsystems with automated desiccant delivery, precision shadow masks for color pixel patterning, and the ability to meet product specifications. This paper discusses the advances made in process integration, reproducibility of display performance, productivity gains, and yield improvement. During two years of production experience, SK Display has made steady progress on its manufacturing learning curve and has already introduced second-generation AMOLED production equipment for 335 × 550 mm glass substrates. The chosen OLED technologies are scaleable to larger glass substrate sizes compatible with existing LTPS facilities. Even though OLED deposition technologies have significantly matured in productivity, yield, and available capacity, substantial improvements in the quality of LTPS substrates suitable for OLEDs is necessary before AMOLEDs can become competitive with AMLCDs.

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.

AMOLED displays with transfer-printed integrated circuits

— Small integrated circuits of crystalline silicon (chiplets) transfer-printed onto a flat-panel-display substrate provide greatly improved electrical performance and uniformity in active-matrix organic light-emitting-diode (OLED) displays. The integrated circuits are formed in high-performance crystalline silicon using conventional photolithographic processes and then transfer-printed onto a substrate using a stamp that transfers hundreds or thousands of chiplets at once. The chiplets are connected to an external controller and to pixel elements using conventional photolithographic substrate processing methods. Active-matrix OLED (AMOLED) displays using transfer-printed chiplets have good yields, excellent uniformity, and electrical performance and are thermally robust.

P-38: Unique Electrical Measurement Technology for Compensation, Inspection, and Process Diagnostics of AMOLED HDTV

A unique measurement and compensation technology for AMOLED high definition television is presented. The technique electrically measures every TFT and OLED in the backplane, useful for inspection and diagnostics in the factory, and subsequent compensation of mura, TFT- and OLED-degradation.

62.3: Exploiting the Flexibility of RGBW OLED Displays: Trading Color Saturation for Power

The RGBW pixel pattern uniquely enables the tradeoff of color gamut for power consumption. A mechanism for achieving these tradeoffs and its application for reducing power consumption by more than 25% for typical images and 10% for typical web pages is discussed.

47.4: Thin, Flexible, Full‐Color, Large‐Area OLED Displays Using Tiles

We have designed and fabricated large-area full-color OLED displays assembled from thin, flexible, lightweight tiles. The tiles were made using barrier-coated PET films, a tandem white OLED formulation with a luminance efficiency of approximately 25 cd/A, and a low-cost externally applied printed color filter.