What are the types of LED?

Answer 1

There are a number of major types of LED which are available and being developed. These LED types are summaries below.

Traditional inorganic LEDs: This type of LED is the traditional form of diode that has been available since the 1960s. It is manufactured from inorganic materials. Some of the more widely used are compound semiconductors such as Aluminium gallium arsenide, Gallium arsenide phosphide, and many more.

These LEDs are typified by the small LED lamps that are used as panel indicators, although there are very many formats for LEDs of this type. However even within the in-organic LED category, there are many different styles of LED:

Single colour 5 mm, etc - the very traditional LED package

Surface mount LEDs

Bi-colour and multicolour LEDs - the types of LEDs contain several individual LEDs that are turned on by different voltages, etc.

Flashing LEDs - with a small time integrated into the package

Alphanumeric LED displays

. . . . . more . . . .

All these different types of inorganic LED are used in very large quantities

Organic LEDs: Organic LEDs are a development of the basic idea for the light emitting diode. This type of LED uses organic materials as the name indicates.

The traditional types of LED utilise traditional inorganic semiconductors with varying dopant levels and they produce light from the defined PN junction - often this is a point of light. The organic type of LED display is based on organic materials which are manufactured in sheets and provide a diffuse area of light. Typically a very thin film of organic material is printed onto a substrate made of glass. A semiconductor circuit is then used to carry the electrical charges to the imprinted pixels, causing them to glow.

High brightness LEDs: High brightness LEDs, HBLEDs, are a type of inorganic LED that are starting to be used for lighting applications. This type of LED is essentially the same as the basic inorganic LED, but has a much greater light output. To generate the higher light output, this LED type requires to be able to handle much higher current levels and power dissipation. Often these LEDs are mounted such that they can be mounted onto a heatsink to remove the unwanted heat.

In view of their greater efficiency, this type of LED is being seen as a replacement for incandescent and the various other forms of energy saving or energy efficient lights such as the Compact Fluorescent Lightbulbs, CFLs. The HBLEDs have a greater efficiency level and they also have a longer life, especially when being switched on and off many times. Coupled with their instantaneous transition to full light output, this type of LED is being seen as the way forwards for lighting applications.