In 1879 it became clear that there was significant commercial potential in lighting and it is not limited to just domestic use. Two events occurred during that year which were to have a far reaching effect on the emergence of a new industry. The first was that a city of USA using a different lamp technology (carbon arc) introduced the first public street lighting. And the second was that patents were registered for the incandescent filament light bulb.
Needless to say the firms involved in gas supply and distribution and the gas lighting industry were not taking the threat from electric light lying down and they responded with a series of improvement and innovations which helped retain gas lighting’s popularity for most of the late nineteenth century. Much of what happened over the next 30 years is a good example of what is sometimes called the sailing ship effect. That is, just as in the shipping world the invention of steam power did not instantly lead to the disappearance of sailing ships but instead triggered a whole series of improvement in that industry so the gas lighting industry consolidated its position through incremental product and process innovations.
But electric lighting was also improving and the period 1886-1920 saw many important breakthroughs and a number of performance improvements. In a famous and detailed study there is evidence to show that little improvements in the design of the bulb and in the process for manufacturing it led to a fall in price of over 80% between 1880 and 1896. Examples of such innovations include the use of gas instead of vacuum in the bulb and the use of tungsten filament.
After an invention there is a period in which all sorts of designs and ideas are thrown around before finally a dominant design settles out and the industry begins to mature. So it was with the light bulb, by the 1920s a tungsten filament inside a glass gas filled bulb was established and the industry began to consolidate. It is this point that the major players Philips, General Electric (GE), Westinghouse become established.
Although the industry then entered a period of stability in the market place there was still considerable activity in the technology arena. In the early 20th century fluorescent lamp and neon lamp were invented and both inventions later can have far reaching effects in terms of the industry and its segmentation into different markets.
The neon lamp started to train work based on forming different glass tubes into shapes for signs and in filling them with a variety of gases with similar properties to neon but which gave different colours.
The fluorescent tube was first made commercially by Sylvania in the USA in 1938 following extensive development work by both GE and Westinghouse. The technology had a number of important features including low power consumption and long life factors which led to their widespread use on office and business environments although less so in the home. By late 20th century florescent lamps advanced along with the traditional filament bulb and a range of compact and shaped fittings were available from the major lighting firms.
Whilst neon and fluorescent tubes were variations on the same basic theme of lights, a different development began in a totally new sector in the 1960s. In 1962 work on the emerging solid state electronics area led to the discovery of a light emitting diode LED a device when a current is passed through it, glow in red or green colour. These lights were bright and used little power; they were also part of the emerging trends towards miniaturization. They quickly became standard features in electronic devices and today the average household will have hundreds of LED’s in orange, green, or red to indicate whether devices such as TV sets, mobile phones, or electric toothbrushes are on and functioning.
Development and refinement of LED’s took place in a different industry for a different market and in particular one line of work was followed in a small Japanese chemical company supplying LEDs to the major manufacturers like Sony. Another company again in Japan began a programme of work on a type of LED would emit blue light – something much more difficult to achieve and requiring complex chemistry and careful process control. Eventually they were successful and in the last decade of 20th century produced a blue LED based on gallium arsenide technology. The firm then committed a major investment to development of both product and process technology.They went on with their research to develop a white light LED using the principle that white light is made up of red, green and blue light mixed together.
LEDs offer the following advantages:
- 85% less power consumption
- 16 times brighter than normal electric lights
- Tiny size
- Long life – tests suggest the life of an LED could be 100 000 hours about 11 years.
LEDs will follow the economies of scale in manufacturing that led to the continuing fall in the price of electronic components and so will become very cheap very quickly.