Introduction to LED

Introduction to LED

New Technology

The lamps that have been used since the invention of the incandescent light bulb some 130 years ago are finally becoming obsolete with the rapid development of LED, Compact Fluorescent and HID light sources.

What are the advantages of using LED lighting?

LED’s can have exceptionally long lifetimes with up to 50,000 hours of useful life (although time to complete failure may be much longer.) This drastically reduces maintenance costs especially compared to halogen luminaires. Fluorescent tubes are typically rated at about 10,000 to 15,000hours and halogen lamps at 1,000 to 2,000 hours. LED’s are far more efficient and produce more lumens per Watt than halogen lamps.
Due to the complete lack of ultraviolet (UV) radiation and infrared (IR)radiation, LED is ideal for display lighting as it does not radiate heat in the direction of the illuminated object, it can therefore be used to illuminate materials that fade easily - food, works of art, etc.

As LED’s are solid state components, they are resistant to damage by impact shock or vibration unlike fluorescent and incandescent lamps which are fragile. LED’s are ideal for use in applications that are subject to frequent on/off switching, whereas fluorescent lamps which can burn out quickly when switched frequently and HID lamps require several minutes before re-starting.LED’s light up very quickly, typically in milliseconds. Dimmable and RGBcolour changing versions are also available for flexibility and control in any lighting application.

In what applications can LED lighting be used?

Display lighting where halogen may fade sensitive materials. Underwater lighting where a low voltage supply for safety is required. Outdoor lighting where coloured effects are desired to enhance outside spaces. Sign lighting, LED strips can be used to light signage in many different colours. Low level lighting where halogen light sources may pose a danger to touch due to high temperatures. Architectural lighting where LED’s can be used in applications which traditionally used expensive and inflexible neon or cold cathode light sources.

Will LED technology save you money?

With todays spiraling energy costs the end user will appreciate lighting cost savings of up to 70% per annum with energy saving LED products compared with halogen lighting. The added benefit of reducing CO2 coupled with a complete absence of Mercury in LED’s, unlike fluorescent lamps, makes LED technology environmentally friendly.

LED (Light Emitting Diode)

A diode is a component that allows an electric current to flow in one direction, but blocks it in the opposite direction. An LED is a diode which emits light when an electric current passes through it.
LED’s are solid state semiconductor devices. LED illumination is achieved when a semiconductor crystal is excited so that it directly produces visible light in a desired wavelength range (colour).
LEDs are small, typically 5mm.
The light from an LED is practically a pure, single colour. A green LED produces green light only, a red LED only red light, and so on. It is the material of the LED chip that determines the colour.
LED’s are driven by direct current, and the amount of current determines the brightness.
The brightness of the LED is proportional to the current flowing through the LED, more current, more light. In order to create a full range of colours including white light, we need to use a selection of different coloured LED’s that can be combined in various proportions to create a wide colour pallete

Features & Benefits of LED

- LED’s are extremely efficient low energy light sources
- In 2005 white LED’s had reached outputs of over 30 lumens/Watt and coloured versions 50 lumens/Watt. The light gains continue to grow, doubling about every two years
- Long operational life of up to 50,000 hours
- Compact light source, no other lamp possesses such small dimensions for a comparative light output
- LED’s do not emit ultraviolet (UV) or infrared (IR) radiation. They do not radiate heat in the direction of the illuminated object, they can therefore be used to illuminate materials that fade easily, food, works of art etc.
- LED’s are durable against impact and vibration
- LED’s can be dimmed
- Coloured light can be produced effectively - over 16 million colours

Common Applications

- Display lighting - compact displays are possible with low operating temperatures
- Display case, museum and shop lighting - illumination of sensitive objects at close range with ultraviolet (UV) and infrared(IR) free light
- Underwater lighting - low voltage supply for safety and low maintenance
- Outside lighting - coloured effects to enhance outdoor spaces
- Sign lighting - strips of LED’s can be used to light signage in many different colours
- Low level lighting - LED luminaires are cool to touch and are therefore suitable for us in domestic situations where childrenmay come into contact with them
- Architectural detail lighting - LED’s can be used in applications which traditionally used neon or cold cathode

LED Colour Variation

Due to the manufacturing process of LED’s they are graded into ‘Bins’ of like colour temperature. Even within these ‘Bins’ it is impossible to guarantee the colour temperature of the light. This colour variation can be discernable to the human eye and this should be taken into account when designing lighting plans using LED technology.

What is RGB?

RGB stands for red, green and blue. It is a commonly used term to denote a module or luminaire that has the ability to change colour, up to a maximum of 16 million variations depending on the controller Features include colour phasing, switching and static colours