Types of LEDs and their main uses

Color LED

LED chips are made up of compounds such as indium, gallium, nitrogen, phosphorus, and aluminum.
Each compound emits a different wavelength of light, which produces different colors.
Generally, InGaN is used for blue to green, and InGaAlP for green to red.

white LED

In the case of a single color, the color is determined by the material of the LED chip, as mentioned above, but white is achieved by mixing two or more colors.
The first method is to use a blue LED and a yellow phosphor, or a red and green phosphor.
The blue light emitted from the LED chip passes through a yellow phosphor or red and green phosphors to become white light.
Only one type of LED chip is required, so the price is low and power consumption is also low.
Additionally, the method using red and green phosphors provides better color rendering than the method using yellow phosphors.
This type of white LED is often used as backlighting for lighting fixtures, displays, and car meters.

The second method uses three LED chips (red, green, and blue) to mix the three colors of light and produce white.
Although the cost increases as the number of chips increases, each chip can be controlled individually, making it possible to produce a variety of colors other than white.
For this reason, it is increasingly being used in illumination lighting and, more recently, in car interiors.

Electromagnetic waves in the area with wavelengths longer than the visible range but shorter than radio waves are called infrared (IR).
Infrared rays are divided into near-infrared, mid-infrared, and far-infrared depending on the wavelength range, and infrared LEDs mainly fall into the near-infrared wavelength range.
Infrared light is characterized by its long wavelength, low energy, and invisibility to the human eye.

Its main applications include remote controls for surveillance cameras, televisions, and air conditioners, etc. In recent years, it has also been used in advanced systems such as DMS (Driver Monitoring System) in the automotive field.

Electromagnetic waves with wavelengths shorter than those in the visible range and longer than those in the X-ray range are called ultraviolet (UV) rays.
It is further divided by wavelength range, and is defined as UV-A, UV-B, and UV-C in order of longest wavelength.
Ultraviolet rays have short wavelengths and high energy.
In particular, UV-C has the shortest wavelength and highest energy, so it is used to disinfect and purify water and air.