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The influence factors of the LED decay

From: Data:10/08/2016

LED lamps as a new type of green lighting lamps , energy saving, environmental protection, long life, by the broad masses of customers to pursue. But the LED decay problem, and a LED lamp has had to face the problem. Uninterrupted decay, serious impact on the use of LED lamps.

, in view of the present situation, market white LED its luminous decay may is to enter the civil lighting is one of the most important problems. What causes the attenuation of LED? Generally speaking, the LED light attenuation are the two major factors:

/> A, product LED itself quality problems:

1, the LED chip constitution bad, brightness decay faster.

2, the production process is flawed, LED chip heat can not be well from the PIN foot export, resulting in LED chip temperature is too high to make the chip attenuation.

two, using the conditions of the problem:

1, LED for the constant current drive, there is a part of the LED using voltage driven reasons for LED attenuation.

2, drive current is greater than the rated driving conditions.

in fact, cause the light decay of LED products for many reasons, the most critical problem is the heat, although many manufacturers in secondary products should not be particularly pay attention to cooling problems, but long-term use of these secondary LED products, attenuation degree will than focus on heat dissipation of LED products. The radiating effect of the LED chip itself thermal resistance, silver glue, substrate and colloidal gold and aspects are and decay.

three LED light effect factors of degradation of quality first, choose what kind of white light LED.

this is very important, the quality of LED white light can be said to be a very important factor. Aging; aging aging aging aging aging low attenuation for the package, with white light with some examples, the same wafer 14mil chip on behalf of common epoxy resin as primer and white glue and glue encapsulation of white LED lamp, single light in 30 degrees, 1000 hours, attenuation data 70%; if the class D ring glue water packaging, in the same environment, thousands of hours of 45%; if the class C low attenuation glue encapsulation in the same environment, thousands of hours of 12%; if class B low attenuation glue encapsulation in the same environment, thousands of hours of failure is - 3% if class a low attenuation glue water, in the same environment, and a thousand hours decline to 6%.

second, LED lamp working environment temperature.

according to a single white LED lamp aging data, white LED lights if only a light work. At the same time, the environment temperature is 30 degrees, so, single LED white light work's bracket temperature not more than 45 degrees. This time, the LED will be a very good life.

if there are 100 pieces of white LED lamp and light work, the interval between them is 11.4mm. Then, bunch of lights surrounding the white LED lamp bracket temperature also may not more than 45 degrees, but the lamp stack in the middle of the white LED lamp could reach the temperature of 65 degrees. This time is a test of LED lamp. Then, gathered in the intermediate to those of white LED lights and theoretical decay will be faster, and the lamp stack around the white LED light, attenuation will slow a bit.

anyway, we should know that LED is afraid of heat, the higher the temperature, the shorter the life of LED, the lower the temperature, the longer the LED life. LED ideal operating temperature of course is in the negative 5 to zero. But it's basically impossible.

so, we know that the ideal parameters for the LED lamp beads, as much as possible in the design of lamps and lanterns, strengthen heat transfer, heat dissipation function. The lower the temperature, the longer the LED life.

again, the design work of electrical parameters of LED beads. LED according to the experimental results,

white light in the case of the lower drive current, the smaller the heat emission, of course, the brightness is smaller. According to the survey, LED solar lighting circuit design, the LED drive current is 5-10mA; lamp beads number with products, such as to achieve more than 500, or more, drive current is 10-15mA, and popular application of LED decorative lamp drive current, just 15-18mA, rarely have the current design to 20mA above.

and experimental results also shows that in 14 Ma drive current, and, along with the windtight cover, inside the air temperature reached 71 degrees of environment, low failure products, thousands of small time decay to zero, 2000 hours of failure is 3%, which indicates that the low attenuation white LEDs used in this environment has reached its maximum, again is a damage to the.

because of aging with the board has no heat sink function, so the heat generated when the LED is basically can not be transmitted to the outside of the. The experiment proved this point. Aging board inside the air temperature has reached a high temperature of 101 degrees, the temperature of the cover surface of the aging board is only 53 degrees, a difference of several tens of degrees. This shows that the design of this plastic lid basically does not have the function of heat conduction and heat. But the general lighting design, are taking into account the function of heat conduction. Therefore, in summary, LED lamp power parameters design to according to the actual situation, if the lamps and lanterns of heat conduction and heat radiation function is very good, white LED lamp drive current increase is no relation of, because the heat generated by the LED lamp bead work moment to export to outside, the LED without damage, is the best care of LED. Contrary, if the lamp heat radiating function careless, it is best to circuit design a small point, let it less and put some heat out.