LED & IRED
LEDs are found in many things we use in day-to-day life. They’re small, effective, efficient for emission of light. LED found in remote control are not there for nothing we often find them useless because it does not emit light but that’s not true they do emit light but it is not visible to humans, light emitted is infrared light & these LEDs are often referred as IREDs.
(IR-infrared E-emitting D-diode)
A light-emitting diode or LED is a semiconductor device that emits visible light when an electric current passes through it. The light is not particularly bright, but in most LEDs it is monochromatic, occurring at a single wavelength.
An LED or IRED consists of two elements of processed material called P-type semiconductor_s and _N-type semiconductor_s. These two elements are placed in direct contact, forming a region called the _P-N junction. In this respect, the LED or IRED resembles most other diode types, but there are important differences. The LED or IRED has a transparent package, allowing visible or IR energy to pass through.
There are many benfits of LEDs compared to conventional devices :
- Low power requirement: Most types can be operated with battery power supplies.
- High efficiency: Most of the power supplied to an LED or IRED is converted into radiation in the desired form, with minimal heat production.
- Long life: When properly installed, an LED or IRED can function for decades.
Typical applications include:
- Indicator lights: These can be two-state (i.e., on/off), bar-graph, or alphabetic-numeric readouts.
- LCD panel backlighting: Specialized white LEDs are used in flat-panel computer displays.
- Fiber optic data transmission: Ease of modulation allows wide communications bandwidth with minimal noise, resulting in high speed and accuracy.
- Remote control: Most home-entertainment “remotes” use IREDs to transmit data to the main unit.
A laser diode, or LD also known as injection laser diode or ILD, is an electrically pumped semiconductor laser in which the active laser medium is formed by a p-n junction of a semiconductor diode similar to that found in a light-emitting diode.
The laser diode is the most common type of laser produced with a wide range of uses that include fiber optic communications, barcode readers, laser pointers, CD/DVD/Blu-ray Disc reading and recording, laser printing, laser scanning, etc.