Portable and handheld lighting devices, AC and DC powered and with different types of illumination sources, are made in many different configurations and sizes. The development of low-cost electroluminescent light-emitting diodes (LEDs) has led to extensive use of this technology in a wide variety of lighting applications and illumination devices. Due to the very high refractive index of uncoated LED semiconductors, for lighting applications LED chips are mounted or encapsulated in plastic as a refractive intermediary to maximize photon emission. Also, the geometry of the chip surfaces can be designed with facets to minimize internal reflection, expand the emitted cone of light, and thereby increase luminous efficacy. Although encapsulated, LED arrays for non-static applications require additional packaging for additional protection, and optical elements which enhance and do not diminish or adversely affect the output lumens.
USPTO Backgrounds
USPTO Backgrounds