LED Basics
What is LED?
LED is an acronym for Light Emitting Diode, a semiconductor device that converts electricity into light.
LEDs are energy-efficient, have a long lifespan, and are environmentally friendly, and are widely used in a variety of applications, including lighting, DISPLAY, and automobile headlights.
LEDs can emit light of specific colors and can produce light ranging from ultraviolet to visible light and infrared.
The history of light sources before the advent of LEDs
The oldest source of light is fire, which was used not only to keep warm but also as light at night.
Later, oil candles came into use and candles became the primary means of lighting.
In the 18th century, INCANDESCENT LAMPS was invented and electric lighting began to become widespread.
In the 19th century, fluorescent lamps were developed and became popular in many places because they were more energy efficient and had a longer lifespan than INCANDESCENT LAMPS.
In the second half of the 20th century, the brightness of blue LEDs increased, leading to the development of white LEDs.
Today, LEDs are widely used as an environmentally friendly lighting solution with high energy efficiency and a long lifespan.
LED lighting principle
LEDs have a polarity due to their DIODES structure.
The P-type semiconductor side is called the anode, and the N-type semiconductor side is called the cathode. Applying a positive voltage to the P-type semiconductor and a negative voltage to the N-type semiconductor is called forward bias.
When forward bias is applied, current flows, causing holes in the P-type semiconductor and electrons in the N-type semiconductor to recombine.
When they recombine, excess energy is released as light.
This is the true nature of LED light.
Conversely, applying a negative voltage to a P-type semiconductor and a positive voltage to an N-type semiconductor is called reverse bias.
When reverse biased, no current flows and the LED does not light up.
LED structure
The internal structure of an LED is shown in the diagram below. We will explain each structure below.
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1. LED chip
The chip emits light when a current is passed through it.
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2. electrode
It provides the conductive contact that allows current to flow to the chip.
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3. Wire
This is the wire that connects the chip to the electrode.
This allows current to flow from the electrode to the tip. -
4. sealing resin
A transparent resin to protect the chip, electrodes, and wires.
Because the resin is transparent, the light emitted from the chip is released to the outside.
*White LEDs may not be transparent due to the phosphor mixed in. -
5. holding resin
Resin used to secure and protect chips, wires, and electrodes.
This retaining resin provides protection from external impacts and environmental factors.
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