Why do LED strip lights become darker and darker after being used for a long time?

2024/04led strip light source

I believe everyone has this life experience. The LED light strips they just bought are always very bright, but after using them for a period of time, the light strips will become darker and darker. What is the reason for this?

Lighting products will have lamp failure. What is lamp failure?

It refers to the process in which the light intensity of the lamp will gradually decrease after a period of use and cannot be restored. The reduced part is called the light decay of the LED.

Light decay generally refers to its luminous flux. When charging the surface of the photosensitive drum, as the charge accumulates on the surface of the photosensitive drum, the potential continues to increase, and finally reaches the "saturation" potential, which is the highest potential. The surface potential will decrease with the passage of time. Generally, the potential during operation is lower than this potential. The process of this potential naturally decreasing with time is called the "dark decay" process. When the photosensitive drum is scanned and exposed, the potential in the dark area (referring to the surface of the photoconductor that is not illuminated by light) is still in the dark decay process; in the bright area (referring to the surface of the photoconductor that is illuminated by light) the carrier density in the photoconductive layer increases rapidly. The conductivity rises rapidly, forming a photoconductive voltage, the charge disappears rapidly, and the surface potential of the photoconductor also drops rapidly. Call it "light decay," which eventually slows down.

Generally, LED light strip packaging manufacturers perform tests under laboratory conditions (normal temperature of 25°C) by continuously lighting the LED with 20MA DC for 1,000 hours to compare the light intensity before and after lighting.

Light attenuation calculation method:

Light decay in N hours = 1-(Light flux in N hours/Light flux in 0 hours)

The longer the LED light strip is used, the darker it becomes. This is because the LED light strip will suffer from light decay.

The degree of light attenuation of current light strip products produced by various manufacturers is different. High-power LED light strips usually have light attenuation, which is directly related to the temperature generated during the use of the light strip, mainly caused by the chip. It depends on the phosphor, packaging, etc.

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