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 also increases continuously, and finally reaches the "saturation" potential, which is the highest potential. The surface potential will decrease over 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 of the dark area (referring to the surface of the photoconductor that is not irradiated by light) is still in the dark decay process; The conductivity rises rapidly, forming the photoconductive voltage, and the charge disappears rapidly, and the surface potential of the photoconductor also drops rapidly. It's called "light decay".
It is a very common phenomenon that LED lights become dimmer as they are used. In addition to light decay, the reasons for dimming LED lights are nothing more than the following two points.
Theoretically speaking, as long as the parameters of the driver match the lamp bead board, the power supply can be continuously supplied and used normally. The inside of the driver is more complicated. The failure of any device (such as capacitor, rectifier, etc.) may cause the output voltage to change, which in turn causes the lamp to dim. Driver damage is one of the most common faults in LED lamps, which can usually be solved by replacing the driver.
The LED itself is composed of lamp beads one by one. If one or part of them does not light up, it will inevitably make the whole lamp dim. The lamp beads are generally connected in series and then in parallel - so if a certain lamp bead is burned, it may cause a batch of lamp beads not to light up. There are obvious black spots on the surface of the burned lamp bead, find it, connect a wire to its back, and short-circuit it; or replace it with a new lamp bead, all can solve the problem.