Chapter 8 - Alternative Flat Panel Display Technologies

Abstract

This chapter briefly describes flat panel technologies competing with active matrix liquid crystal display (AMLCDs). These technologies include plasma displays, inorganic and organic electroluminescent displays, and front and rear projection. These technologies each represent a large field in themselves, with numerous publications and continuing development. The purpose of this chapter is to describe competing technologies and discuss a perspective on the merits and drawbacks of AMLCDs relative to other successful and less successful flat panel display technologies. Since the manufacturing of AMLCDs requires expensive, semiconductor-type processing, it has been difficult to replace cathode ray tubes (CRTs) and plasma display panels (PDPs) with a lower manufacturing cost structure in all applications. LCDs are non-emissive and need external light sources to be legible. The self-emissive displays can be classified in plasma display panels (PDPs), field-emission displays (FEDs), and inorganic and organic electroluminescent displays. As compared to LCDs, all emissive display technologies have some distinct advantages and drawbacks. They have perfect viewing angle behavior and are self-emissive, not requiring an external light source. They can also have zero luminance in the dark state. This compares favorably with LCDs, in which the backlight is permanently ON and contrast ratio is limited, especially at oblique viewing angles. There will be some residual luminance in the dark state of LCDs. Emissive displays have higher reflectance, rapidly losing contrast at higher ambient lighting levels. To reduce reflectance, contrast enhancement filters such as polarizers or neutral density filters can be added in front of the emissive display at the expense of luminance.