There are a broad range of application-specific needs for lighting and display technologies used in homes, workplaces and consumer products. Lighting and display applications require color purity and tailored control of the optical properties of their output. For example, the directivity or diffusivity of a light source affects user comfort under various lighting conditions and the directionality of light output from displays affects the viewing angle, allowing either privacy or accessibility to groups.
Light emitting diodes (LEDs) are important light sources in many applications such as solid state lighting, back lighting, signaling and displays. As in conventional light sources LEDs are non-coherent and non-polarized light sources, i.e. light does not possess a significant preference for a specific polarization state. However, for certain applications, such as liquid crystal display backlighting, liquid crystal display projection, and liquid crystal beam steering devices in which the light beam emitted by LED point sources is manipulated with liquid crystal cells, the non-polarized light from LEDs must be converted to polarized light through a polarizer so that the next layer of liquid crystal can switch the light from LEDs on and off. The required polarizer adds cost and complexity to such displays.
It would be desirable to have improved light-emitting structures.