The ABCs of LED Technology
Q: What is “LED” ?
A: A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode, which emits light when activated. When a suitable voltage is applied to the leads, electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor.
Q:How does LED work?
The structure of the LED light is completely different than that of the light bulb. Amazingly, the LED has a simple and strong structure. The beauty of the structure is that it is designed to be versatile, allowing for assembly into many different shapes. The light-emitting semiconductor material is what determines the LED’s color.
As indicated by its name, the LED is a diode that emits light. A diode is a device that allows current to flow in only one direction. Almost any two conductive materials will form a diode when placed in contact with each other. When electricity is passed through the diode the atoms in one material (within the semiconductor chip) are excited to a higher energy level. The atoms in that first material have too much energy and need to release that energy. The energy is then released as the atoms shed electrons to the other material within the chip. During this energy release light is created. The color of the light from the LED is a function of the ingredients (materials) and recipes (processes) that make up the chip.
Q: What is the advantaged of LED Lightings ?
LED lights have a variety of advantages over other light sources:
- High-levels of brightness and intensity
- Low-voltage and current requirements
- Low radiated heat
- High reliability (resistant to shock and vibration)
- No UV Rays
- Long source life
- Can be easily controlled and programmed
Q: What’s the benefits of LEDs?
Benefits of LEDs , compared with incandescent and fluorescent illuminating devices, include:
- 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.
Q: Where use the LEDs?
- Indicator lights: These can be two-state, 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.
- Optoisolator: Stages in an electronic system can be connected together without unwanted interaction.