With the development of science and technology, city’s lighting demand increase rapidly, When the night coming, all over the city with colorful lights. Today, everyone wants to make the place where live or work beautiful and bright with lighting. Therefore, people like to design and install various lighting when decorating house, office, school etc… After that, the high electricity cost become a headache. We may know the news from TV said that the government is encouraging upgrade traditional lights to LED lighting which can help save a lot of energy. However, when we find that LED lamps price are much higher than those traditional lamps, we have to wondering “How led lights can save electricity and energy at home? We will analyze and compare LED lights and ordinary lamps from various aspects, and see if it’s worth to upgrade from conventional lamps to LED.

Compare LED lights with traditional lamps.

1, The principle of luminosity for various light sources.

1.1 Luminescence Principle of Incandescent Lamp

Incandescent lamp is a device that converts electrical energy into light energy to provide lighting. Its working principle is that electricity converted into heat, and the filament is heated to a very high temperature (tungsten wire, melting point of more than 3000 C). At this time, the extranuclear electrons of the elements that make up the filament will be stimulated, so that they can transit to the outer layer of higher energy. When the electrons transit to the lower electron layer again, the excess energy will be emitted in the form of light. At the same time, heat is generated. The spiral filament keeps gathering heat, making the filament temperature above 2000 C. When filament is incandescent, it emits light just like burnt iron. The higher the filament temperature, the brighter the light emitted. So it is called incandescent lamp.

Disadvantages: 1) High energy consumption: low luminous efficiency, not conducive to energy saving; 80% heat generated, only 20% light.

2)Lifespan is relatively short and generally about 1000 hours.

3) Single color: its warm color and yellow light, sometimes not necessarily popular.

4) Easy to damage: glass products.

 

1.2 Luminescence Principle of halogen lamp

halogen lamp is produced by mercury vapor ionization, ultraviolet light makes halogen  powder glow. Mercury does not completely turn into mercury vapor when the light is turned on, so the light is darker when the light is turned on, when all Mercury turn into mercury vapor lamps can completely lights up.

In addition, it should be noted that “most of the energy-saving lamps we use now are tri-primary and halogen powder”, which are “produced by mercury vapor ionization to produce ultraviolet light to make fluorescent powder (tri-primary or halogen powder) glow”. This is the basic principle of energy saving lamp and halogen lamp.

Disadvantages: 1). Energy-saving lamp is very bright and flickering phenomenon, has an impact on the eyes.

2) Mercury pollution occurs during the production process and after the use of waste mercury. At present, western countries attach great importance to mercury pollution.

3) Because of glass products, they are fragile, difficult to transport and install.

4) Their electricity consumption is still too high.

5) Easy to damage, short life, energy saving and no money saving is its best portrayal.

 

1.3 Luminescence Principle fluorescent lamp.

The fluorescent tube is equipped with filaments at both ends, and the inner wall of the glass tube is coated with a uniform thin phosphor. After the tube is pumped into a vacuum 103-104 mm mercury column, a small amount of inert gas is filled into the tube, and a small amount of liquid mercury is injected at the same time. The inner wall of the lamp tube is coated with phosphor. When the gas between the two filaments conducts electricity, it emits ultraviolet light, which makes the phosphor emit soft visible light.

Blackening at both ends of the lamp: tungsten wire sublimation directly into tungsten gas, these tungsten gases encounter lower temperature lamp wall and condensation on the lamp wall and blackening, when tungsten wire sublimation to a relatively thin, it is easy to burn after electrification.

Disadvantages of fluorescent lamp: (1) There are many accessories of fluorescent lamp, and there are many chances of failure.

(2) Fluorescent lamps are more expensive than tungsten filament incandescent lamps.

(3) The power of fluorescent lamps cannot be very high.

(4) Fluorescent lamp is the appearance of flickering stroboscopic

 

1.4 Luminescence Principle of LED light

Light-emitting diodes (LED) are made of III-IV compounds, such as GaAs (GaAs), GaP (GaP), GaAsP (GaAs) and other semiconductors. The core of the LED is PN_junction. Therefore, it has the I-V_characteristics of general P-N_junctions, i.e. forward conduction, reverse cut-off and breakdown characteristics. In addition, it has luminescent properties under certain conditions. Under forward voltage, electrons are injected into P_region from N_region and holes into N_region from P_region. The minority carriers (minority carriers) entering the opposite region are combined with the majority carriers (polycarriers) to emit light.

What are the advantages of LED light?

  1. Energy saving. LED energy consumption is only 1/10 of incandescent lamp, energy saving 1/4 of fluorescent lamp
  2. Long life. Life can reach more than 50,000 hours, for ordinary household lighting can be described as “once and for all”.
  3. It can work at high speed. If the fluorescent lamp is turned on or off frequently, the filament will turn black and spoil quickly..
  4. Solid-state packaging, which belongs to the type of cold light source. So it is very convenient to transport and install, can be installed in any micro and closed equipment, not afraid of vibration, basically without considering heat dissipation.
  5. LED technology is progressing rapidly. Its luminous efficiency is making an amazing breakthrough, and its price is constantly decreasing. The era of LED entering the family is rapidly approaching.
  6. Environmental protection, no harmful substances of mercury. The assembly parts of the LED lamp can be easily disassembled and assembled, and can be recovered by other people without manufacturer’s recycling.

Disadvantage: At present, the development cost is high and the price is relatively high.

Summary: Obviously, following the cost of LED light decreases with the continuous improvement of LED technology. fluorescent lamp and incandescent lamp will inevitably be replaced by LED lights. At present, the countries pays more and more attention to energy saving and environmental protection of lighting, and has been vigorously promoting the use of LED light. Until 2018, the led light price only 30% higher than the CFL lamps.

Experimental data compare(LED vs CFL vs Incandescent vs  fluorescent) light efficiency, life span, toxic substance, reaction rate and CRI

LED vs. CFL vs. Incandescent Light Bulbs

Data from Weshine Technology’s China LED Light Manufacturers: Complete Analysis