Source: Site Time:2018-10-26
1. Misunderstanding 1, the expectation of the actual service life is too high.
LED lighting manufacturers expect LED lifetimes to reach 100,000 hours MTBF (mean time between failures, the standard used by traditional luminaire manufacturers to measure lamp life). However, like all basic light sources, the luminous flux of an LED is also attenuated over time. Therefore, although the LED illumination time can be very long, MTBF is not the only consideration for determining the service life. The attenuation of LED lumens is affected by many environmental conditions such as ambient temperature, humidity and ventilation. Lumen attenuation is also affected by control, thermal management, current levels, and many other electrical design considerations.
Many salesmen may give customers some ambiguous information for some reason when selling LEDs, which is misleading. For example, the service life of LEDs is about 100,000 hours, and the 100,000 hours here refers to the expected life of LEDs. However, as the light source of illumination, the brightness of the lamp has a process of gradually attenuating and dimming (such as a fluorescent lamp, an energy-saving lamp), and this process is referred to as light decay. Therefore, consumers should pay attention to the speed of light decay when purchasing LEDs, rather than the time of use. Consumers should not expect too much from the actual service life.
2. Misunderstanding 2, the actual luminous angle is taken as an effective angle.
The illumination angle of the LED is divided into an effective angle and an actual illumination angle. The angle at which the luminous intensity value is half of the axial strength value and the angle of the luminous axis (normal) are effective angles. The angle of view of the half angle angle (or half power angle) is the actual light angle. Angles other than half of the axial strength are not considered effective angles in practical applications because the light is too weak.
Therefore, consumers should pay attention to the actual lighting angle of the product when purchasing products. When calculating the number of products used in the project, the actual lighting angle is the standard, and the effective lighting angle can only be used as a reference value.
3. Misunderstanding 3, the higher the power, the higher the brightness.
The brightness of an LED is measured by the intensity of the illumination, which is the luminous intensity in the direction of the normal (to the axis of the cylindrical luminous tube), that is, the luminous flux emitted by the unit solid angle, in units of candle light (Candela, cd). Since the luminous intensity of a general LED is small, the luminous intensity is usually measured in millicald (mcd). Generally speaking, the light source emits its luminous flux with different intensity in different directions, and the visible light radiation intensity emitted by the solid angle in a specific direction is called light intensity, which is simply referred to as axial brightness.
The concept of electric power is introduced from the amount of work done in equal time. The current is fast and the electric power is large; the current is slow, the electric power is small, or the electric work is more in the same time, the electric power is larger. On the LED, the higher the power, the higher the brightness of the product. Taking Yimei Electronics' three-lamp red LED as an example, when the axial brightness is 1200mcd, the current is 40ma and the power is 0.48W; the three-lamp white LED has the same brightness, the current is 18ma, and the power is only 0.24W; The power of the two lights at the same brightness is different. Therefore, consumers should pay attention to its axial brightness, not power, when purchasing LED lamps.