Display technologies

The current-voltage and luminance-voltage characteristics of a state of the art polymer LED [3] are shown in Figure 11-2. The luminance of this device is roughly 650 cd/m2 at 4 V and the luminous efficiency can reach 2 lm/W. This luminance is more than adequate for display purposes. For comparison, the luminance of the white display on a color cathode ray tube is about 500 cd/m2l5J. The luminous efficiency, 2 lm/W, is comparable to other emissive electronic display technologies [5], The device structure of this state of the art LED is similar to the first device although a modified polymer and different metallic contacts are used to improve the efficiency and stability of the diode. Reference [2] provides a review of the history of the development of polymer LEDs. 

The paper is oiganized to describe, first, the materials that have been used in OLEDs, then the device structures that have been evaluated. After a description of the methods used to characterize and evaluate materials and devices, we summarize the current stale of understanding of the physics of device operation, followed by a discussion of the mechanisms which lead to degradation and failure. Finally, we present the issues that must be addressed to develop a viable flat-panel display technology using OLEDs. Space and schedule prevent a comprehensive review of the vast literature in this rapidly moving field. We have tried to present... 

In this section, we provide a brief introduction to the field of display engineering and the human-factors issues which dictate display design. We then assess how OLEDs measure up to the criteria necessary to achieve a commercially successful display technology. But first, we take a short detour to lay out the language used by display engineers and to provide a means of translating from the scientific units that wc have used up to now. 

Liquid crystals, commonly referred to as the fourth state of matter, are materials which are intermediate in character between the solid and liquid states. Unlike normal isotropic liquids, they show some time-averaged positional orientation of the molecules, but they retain many of the properties of liquids, such as the ability to flow. In recent decades, liquid crystals have played an increasingly important part in our lives. Probably their most familiar application is in the information displays which provide the visual interface with microprocessor-controlled instrumentation. Liquid crystal displays have superseded more traditional display technology, such as light-emitting diodes and cathode ray tubes, for many appliances principally because of the advantages of visual appeal, low power consumption, and their ability to facilitate the miniaturisation of devices into which they are incorporated. They are encoun-... 

Mentley, D. E. 2002. State of flat-panel display technology and future trends. Proc. IEEE 90 453 159. 

MacDonald, W. A. 2004. Engineered films for display technologies. I. Mater. Chem. 14 4-10. 

Figure 13.2 Phage display technology and the screening of a library for a protein capable of binding to a desired target molecule. In this simplified example an initial library of three genes is inserted into three phages. One (gene 2) codes for the desired protein. In reality, libraries typically consist of hundreds of thousands/mil-lions of different genes. Refer to text for further details...

Humira (EU USA also sold as Trudexa in EU) (adalimumab r (anti-TNF) human monoclonal antibody created using phage display technology Cambridge Antibody Technologies Abbott (USA) Abbott (EU) Rheumatoid arthritis... 

He, M. and Khan, F. 2005. Ribosome display next generation display technologies for production of antibodies in vitro. Expert Review of Proteomics 2(3), 421-430. 

The applications for electronics discussed so far are generally not apparent to the consumer they are effectively invisible. However, during operation, the use of electronics becomes obvious to the consumer, not least due to the ever-improving display technology. 

O Improved operating and display technology also by the use of electronics. 

Winter G, Griffiths AD, Hawkins RE, Hoogenboom HR. Making antibodies by phage display technology. Annu Rev Immunol 1994 12 433 -55. 

As mentioned in this review, AMPLEDs are especially attractive for motion picture applications. The Pay-Per-View effect in OLED displays reduces power consumption and extends operation lifetime. Motion picture applications also minimize image retention and optimize display homogeneity. AMOLED has been widely viewed as a promising display technology in competing with AMLCD and plasma displays. The dream of using organic semiconductor films for optoelectronic device applications has become a reality. 

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