What is LED?
Light Emitting Diodes (LED ) are increasing gaining favour in both the domestic and commercial sectors; due to their efficiency, sustainability and durability.
How does an LED produce light and why is it so low energy?
LED are semiconductor devices, which work on the movement of electrons. This movement of electrons converts the energy supplied to the LED into protons, producing light. This process is called electroluminescence.
Depending on the band of energy used by the semiconductor in the device, an LED can be a number of different colours and can be used in a variety of ways, from creating the infra-red beam in your TV remote, to providing white light for illuminating your home.
Domestic LED bulbs designed for the retrofit market currently use between 3 and 8W of energy in comparison to the massive 35 - 50W of a standard Halogen bulb and are usually more efficient even than CFL lighting. The lifetime of an LED also makes it a more attractive low energy option, with some manufacturers quoting 50,000 hours.
Different types of LED light sources
COB stands for Chips on Board and is a lighting systems that uses multiply LED chips grouped together to form a panel of light. These systems are compact but very bright and have a high thermal performance due to their aluminium base, which spreads out heat very efficiently.
SMD, or surface mount LED, are LEDs that are fitted onto circuit boards. These LEDs are normally tiny in size and are used for backlighting, on the dashboards of aircraft and for the lights on your keyboard. However, SMDs can also be mounted together to form enough light for a domestic bulb.
Luxeon LEDs are powerful white-light producers, which were first introduced in 1999, by the Lumileds Corporation of California. One of their main uses has been for the lighting of torches, with 5mm LEDs placed into groups to provide a strong beam. Unlike old tungsten filament torches, LED torches do not require heat to create their light, making them much more efficient.
The CREE Corporation, formed in 1987, California, provides a range of energy efficient LED lighting products. Like Luxeon LEDs they are also used to create strong, efficient torch beams, but CREE LEDs can come in a range of different colours and brightness for lighting the home inside and out.
An OLED is an organic lighting-emitting diode, and uses a film of organic material to produce its electroluminescence. The organic semiconductor is fitted between two electrodes, with OLEDs most often used to create clear digital images for the screens of portable game consoles, televisions, computers and mobile phones.
Constant Current Vs Constant Voltage
When switching to LEDs you may have to consider your transformers, as LED’s low wattage mean they are sometimes unable to meet the minimum 20W required by most standard transformers. The two types of drivers you can choose from are constant current and constant voltage. Constant current drivers are best used to power a single bulb or when running a number of bulbs in a series. When running numerous bulbs in parallel, a constant voltage driver is better.
LED colours and what they mean
The Kelvin scale measures colour temperature, which is connected to the quality of the lighting you receive. Even the colour white can have different colour temperatures and different colour quality; for example LEDs with a colour temperature of 3000K have a warmer white effect than white LEDs which have a temperature of 6000K, which creates a cooler white. Cooler white LEDs are most often used in a factory or commercial setting, with the warmer 3000k LEDs more suitable for the home.
The most energy efficient bulb - but what’s the cost?
LEDs are used for both commercial and domestic purposes in the form of backlights and bulbs, for use in screens, torches, lamps, dashboards and much more. Their initial cost may be steep in comparison to other light sources (around £15 for a bulb), but with 50,000-75,000 hours life years of guaranteed use, not to mention the lower energy consumption, LED lighting is most definitely the future.