At present, LED illumination lamps and lanterns are more and more popular and pervasive with the explosive growth of LED industry output value. Moreover, people have fallen in love with LED lights and can’t leave them in daily life and work.

However, because of poor LED technology standard, excess production capacity and cutthroat competition between enterprises, many of LED lighting products aren’t good in quality. Also, people know no much knowledge about LED lights when choosing them.

Keep it in mind with the advices of the following three wrong assumptions:

Assumption One: Have excessive expectations to actual service life of LED lights

Generally, LED manufacturer anticipate LED service time up to 100,000 hours MTBF (Mean time between failures-standard that traditional lamps manufacturers use for measuring lifespans of light source). But the LED luminous flux lumens also decrease over time like more all of basic light source. Therefore MTBF isn’t the unique considering factor to confirm the service life of LED even through the time of LED lighting is very long. The attenuation of LED lumens is affected by some environmental conditions, such as temperature, humidity and ventilation, also including control, thermal management, current level and other electric design factors.

So with the light source, brightness of light has a gradually attenuation and dimming process and this process is called lumen decrease.

When you buy LED lamps and lanterns, what you focus on is the speed of lumen decrease but not service life. Do not have excessive expectations to actual useful life.

Assumption Two: Consider actual beam angle as effective angle

The beam angle of LED includes effective angle and actual beam angle. The included angle between direction of which luminous intensity values are half of axial intensity values and direction of lighting optic axis is named effective angle. The viewing angle of double half-value angle is named actual beam angle. The angle which is beyond half of axial direction intensity isn’t calculated in effective angle because of too weak light ray.

When you buy LED products or calculate the amount of LED lighting products in project, you should focus on the actual beam angle and effective angle is only looked as reference.

Assumption Three: The more power the brighter the LED

The brightness of LED is measured with luminous intensity that is a photometric quantity measured in lumens per steradian (lm/sr), or candela (cd/mcd). Generally, light source can emit different luminous flux to different directions and the visible light radiation intensity which emits from unit solid angle in specific direction is light intensity or axial direction brightness for short.

In electric power, the faster current is, the higher electric power is. However, about LED power, it is not that the more power is, the higher brightness is.

For example, one lamp in two modes from Spark, first mode-axial direction brightness 1200mcd, current 40ma, power 0.4w; second mode-axial direction brightness 1200mcd, current 18ma, power 0.24w. From this figures comparison, we can know that the power is different in same brightness. In other words, the saying that the more power is, the higher brightness is is wrong.

When we choose LED lamps and lanterns, we should pay attention to axial direction brightness or luminous intensity not power.