Tungsten filament bulbs are gradually be phased out in the UK but they have some advantages over the other bulb technologies on the market. They achieve maximum light output very quickly and emit a broad spectrum light, whichis much closer to daylight than many other types of bulbs. They can also output high levels of light. The down side of filament bulbs is that they are not very efficient and a lot of heat is produced as well as light. They also have a reputation for being short lived but, this is simply the result of them being designed down to a price.
A lot of claims are made that low energy light bulbs last longer but, filament bulbs can last as long as they are designed to. To save costs and encourage people to replace them, they are often designed with a lifetime of around 1000-2000 hours. Switching the on and off repeatedly will also reduce they lifetime due to the thermal shock on the filament.
Compact Flourescent (CFL) 'Low Energy'
Many people don't like low energy bulbs because of the time lag in reaching full brightness, though modern versions are much better in this respect. They can also flicker on switch on and the colour temperature is not as pleasing to the eye. On the plus side, a 11W low energy bulb can provide as much light as a 60W incandescent bulb and they typically last 4000-8000 hours
Field-Induced Polymer ELectroluminescent (FIPEL)
Scientists at the Wake Forest University have created a new type of light bulb that promises to be just as efficient as LED equivalents, but without any of the drawbacks. The new field-induced polymer electroluminescent bulbs (FIPEL) produce light when an electric current is passed through the nano-engineered plastic layers. The bulbs are malleable, allowing them to be made in numerous shapes and they will not shatter. They are also silent and don't flicker. The inventors believe the new solution to be superior to LED bulbs in terms of brightness, lower heat generation, a colour temperaure closer to natural sunlight and a longer life-time. The new bulbs should be on the market in 2013.
Halogen bulbs are also very popular but, also generate a lot of heat. Our experience is that the 240V ac bulbs are not very reliable because of the excessive heat produced. In 12V form, they have been very reliable though.
Luminex isn't a lighting technology as such. It is a fibre-optic, light distribution technology that is worthy of mention though and is used in fashion and decorative applications.
Full spectrum or 'daylight' light bulbs use a rare earth element called neodymium which absorbs the yellow spectrum from the visible light. Neodymium light bulbs enhance the blues and reds and make colours appear more vibrant. In comparison, ordinary light bulbs produce a harsh unnatural light that can contribute to glare and eye strain. Neodymium bulbs simulate full spectrum light similar to true daylight.
Since they mimic the qualities of natural sunlight, are very appropriate for individuals who suffer from Seasonal Affective Syndrome (SAD). Natural daylight has always had desirable qualities, and is often recommended for improving mood and motivation. Most people will agree, working in an office with no windows can be depressing. The cold winter months and overcast seasons can also be gloomy, but full spectrum light bulbs can make the indoors look like the height of summer.
Full spectrum light bulbs are made of a special hand-blown glass that is not coloured or coated, but instead contain a rare earth element, neodymium. This element absorbs yellow and other dulling components of the spectrum and produces a purified light that is whiter and brighter than light obtained from standard bulbs. The light from Full spectrum light bulbs enhances black and white on written pages and makes colours appear more accurately. Houseplants and pets will also benefit from the Plant Lamp; it provides plants with the specific wavelength of light required and is recommended as a sun simulating light source for captive indoor pets.
LED lighting is slowly taking off in consumer use. Take up is being limited by the available light output and relatively high host. LEDs are very efficient at converting electrical energy into light though and are also very reliable. Cheap and poorly designed driver circuits are the most common cause of LED bulb failure as the LEDs within them can usually survive over 100,000 hours of use.
A lot of LED lighting claims to have no or low Ultraviolet (UV) light output.
Advances in LED technology continue to be made. MIT recently (March 2012) announced an LED that puts out more power than is pumped in.
In terms of efficiency modern LED bulbs are now the best. They can be relatively expensive though and quite cold in colour. There are 'warm white' LED lamps available though and colour changing bulbs are in vogue right now too. It is worth bearing in mind that LEDs are not that much more efficient than CFL bulbs though. The US Department of Energy estimates are $1.00 to run an 'Energy Star' certfied LED bulb for two hours a day each year, compared to $1.20 a year for an equivalent CFL.
Organic LED (OLED)
An amazing video of Philips Lumiblade lighting technology:
Zero Power Lighting
Believe it or not, you can use lights in your home which consume no power at all. Tritium lights use an air-tight sealed glass tube coated on the inside with a luminous substance. The coating is 'fired' with electrons emitted by the tritium gas which causes the layer to light up (when such an electron hits the powder layer a fraction of its kinetic energy is transformed into light). The electrons are created through the radioactive disintegration of tritium (an isotope of hydrogen). Tritium is unstable and disintegrates whilst sending out beta radiation (electrons) with a half-life time of 12.3 years to helium. The electron is unable to penetrate the human skin and can be stopped without any problems by a sheet of paper.
In this case we mean 12V ac and dc lighting.