For many years, Electronic displays

For many years, Electronic displays have been the window to the world in television as well as the primary human interface to computers. In today's information society, they play a crucial and indispensable role in communication, computing, and entertainment devices. This chapter provides an overview of this technology starting with the historical perspective. Liquid crystals were discovered by Reinitzer in 1888. Liquid crystals are an intermediate phase between crystalline solids and isotropic liquids, and combine certain characteristic properties of the crystal structure with those of a deformable fluid. Display devices utilize both their fluidity and the anisotropy associated with their crystalline character. The anisotropy causes the dielectric constant and refractive index of the LC fluid to depend on the orientation of its molecules. Most liquid crystal displays (LCDs) rely on the manipulation of polarized light to generate an image based on data from an electronic signal source. LCDs are non-emissive. The twisted nematic (TN) mode of operation forms the basis of many practical LCDs. This can be ambient lighting in the case of the reflective display in a calculator, or a backlight in the case of a transmissive display in a notebook computer. The electro-optical behavior of the liquid crystal layer modulates the light from the external light source to form an image or pattern corresponding to the electronic data signal information supplied to the display pixels. This chapter closes with an account on the limitations of passive matrix addressing.