Why is LED lighting better than other lighting sources?

With technological development, LED has been widely applied for our daily lives. It has obvious advantages than other lighting sources. Lighting is one of human’s great inventions, we can exploit the night time and dark space because of it. Now let us learn more about the lighting sources.
The ancient butter lamp, its luminous efficiency is below 5%.

Human’s ancestors ignited a stack of firewood for lighting in ancient period. Afterwards, human invented butter lamp, candle, kerosene lamp and acetylene lamp, etc, its lumen is more and higher and easier to use. Subsequently, Faraday brought electric power for human being, Edison invented incandescent lamp which can be lightened by electric power, from then on, human’s lighting entered into a new era, no matter it is brightness or convenience, they also extremely surpassed traditional fuel-burning lamp.
Incandescent lamp, its luminous efficiency is less 15%.

It was in nearly 100 years after incandescent lamp being invented, this lamp which is to exploit electric tungsten filament inside vacuum glass bulb to bright has dominated the global lighting industry, although there are fluorescent lamp, iodine-tungsten lamp and xenon lamp, etc, they can’t replace the domination of incandescent lamp, until the appearing of LED.

LED is Lighting Emitting Diode, it is a semiconductor material which can bright after getting through current. LED was born in the General Electric laboratory in 1962. Usually, LED was made by gallium arsenide, gallium phosphide, carborundum and gallium nitride, etc, different materials would distribute different lighting color. For example, gallium arsenide LED can bright red lighting, gallium phosphide can bright green lighting and gallium nitride can bright blue lighting, etc.
Gas Energy-Saving Lamp, its luminous efficiency is around 50%.

It was during 30 years after the invention of LED, as its low brightness and single lighting color, LED was just used for indicator and single screen fields, while it can’t be used for more illumination. It was up to 1990s, Japanese scientist invented blue LED lighting which was made by gallium nitride and indium gallium nitride materials, since then LED was gradually used for daily lighting fields.

Maybe you would feel strange that why LED was universal after blue LED lighting being invented, and now the LED lighting is not blue color. In order to explain this question, we should learn more about our daily requirement lighting. The lighting which is used for night illumination is better to include red, orange, yellow, green, cyan, blue and purple, so that we can view the natural color of objectiveness. If lighting sources don’t include these lighting colors, the color of objectiveness that we view under lighting is different with its natural color. This phenomena that lighting to restore object color is named as CRI (color rendering index), it is an important criteria to measure LED lighting quality.

The power of light-wave is gradually decrease from purple, blue to orange, red. A layer of fluorescent powder covers on the blue LED lighting, an entire lighting can output after being motivated by blue LED lighting, this entire lighting look seems white color lighting. As the light-power which is motivated by fluorescent powder can’t be higher the light-wave of illumination, so the blue lighting color which is in the high-power position would be lost if using green, red lighting color to motivate, then it can’t be used for illumination.

Why is LED greatly applied because of energy-saving? This would relate to luminous efficiency of various of lighting sources. The lighting sources which are used for illumination would consume power to convert into light-power, at the same time, it would also have a lot of heat power. Just light-power is useful for illumination, the heat-power is useless power consumption. For lighting, the higher of its luminous efficiency, the lighting source would be better.
The earlier LED, power is small and color is single

The ancient butter lamp is just about 15% of power to convert into light-power, other power would convert into heat-power which is a wastage. While the luminous efficiency of incandescent lamp is just 10%-15% even if its tungsten filament is to 3000 degree, other 85% has converted into heat-power. The luminous efficiency of fluorescent lamp and gas lighting energy-saving lamp can reach 50%, so it can save about 80% of power than incandescent lamp under the same brightness and its lifespan is far longer than incandescent lamp. But there is a big problem for fluorescent lamp and gas energy-saving lamp, that is because it need use a lot of poisonous materials, such as fluorescent powder, mercury vapor, etc. This lamp would have severe environmental pollution after being damaged or discarded as useless.

In recent years, the luminous efficiency of LED has got greatly improved, presently, 200LM/W LED has appeared, its luminous efficiency has surpassed 60%. Usually, the luminous efficiency of LED is 40%-50% for illumination, which is similar with fluorescent lamp and gas energy-saving lamp. While LED is smaller size, longer lifespan, environmentally friendly, better performance for CRI and low cost, therefore, LED is development tendency in future.

Bingsolar, 3th, September, 2018