Development of LED bulb

Enter year 2011, LED lighting switch to indoor lighting gradually, which means the beginning of entering in to the civilian families. On hand this is a giant happy event, because the civilian market is very large; the other hand is a very serious challenge, because the civilian market demands low cost, high reliability. Now it is very far to meet the requirements of the civilian market, they can say it is still a long way to go.

The most common commercial lamp is incandescent lamp, what they use most. So if use LED in lieu of incandescent bulbs, it is necessary to create bulb, its head shape or appearance are similar to incandescent bulbs. This is what they regularly talked as LED bulb. Imagine, the marketplace for such bulb is immense.

I. Request of LED bulbs:

 To replace incandescent bulbs, there’ll be following requirements:

 ① Equivalent luminous flux 

 ② Pear shaped

 ③ Equivalent size

 ④ Equivalent weight

 ⑤ Similar base, such as E26 or E27

 ⑥ Similar input voltage, such as 220V AC or 110V AC

II. PAR lamps

PAR lamps is actually a high-power halogen lamp, commonly call as PAR lamps or spot lamp. To be compatible with PAR lamps, the high-power LED PAR light is requested in the same size, while in different structures, different wattage, different brightness. PAR30 and PAR38 lamps are shown in the image below. And compatible LED PAR lamps, they are exactly the same size and shape.

                               PAR30 and PAR38

LED PAR Lamps

After using LED, due to no uniform specifications, there’re a variety of performance indicators. Here’re some typical lamps compared with original halogen lamps:

The unit for luminous intensity differs, Figure 1 uses cd (candlelight), and the LED is typically measured in lm (lumens). Relationship between the two is as follows: φ (lm) = 4πI (candlelight). But due to the two different emission solid angle, there’s no conversion. Only broadly speaking, halogen light’s luminous efficiency is about 17-33 lm / W. The LED luminous efficiency is 100-130lm / W. about 4-6 times higher than halogen lamps. PAR lamps have the same structure as led bulbs, but the larger size, larger wattage.

III. Market Prospects

According to official estimates, LED annual growth rate is over 30% until year 2014. To replace all incandescent lamps, the global market scale will reach 640 billion U.S. dollars. Till December 2010, LED bulb sales are twenty million, only three.2% of its market penetration. It is expected to reach 12.5% in 2013. That is the equivalent of $ 80 billion in sales. And its cost will be an annual rate of 15-20% descending. led bulb to replace a 60W incandescent lamp was sold at $ 90 in 2008, while at $ 40 in 2010.

Now the highest luminous efficiency of LED is about 140lm / W. To year 2020, it is expected to be upgraded to 240lm / W. Thus power consumption, heat sink size and weight can be reduced, further cost of LED Bulbs can be lower. At that time, the time of fully replacing incandescent light with led bulb is coming.