Label：Embedded LEDs, Aging Test, Soldering Process
Mar 24, 20224442
JRPanel has long launched a membrane switch with embedded LEDs. Although the LED power on the membrane switch is not large, how to effectively prevent its aging is also one of the issues that JRPanel continues to focus on.
Today, the engineers of JRPanel would like to share a few points with you on this problem.
Generally speaking, the luminosity of the LED will have a certain attenuation during the initial lighting stage. In order to provide stable luminous products to application manufacturers, or to obtain stable LED materials, LED packaging factories usually do some aging tests. Of course, there are many ways of LED aging test, such as conventional aging, overcurrent impact destructive test and so on.
LED manufacturers usually perform the following aging tests:
1. Multi-tube series aging test: constant voltage aging circuit and constant current aging circuit;
2. Multi-tube parallel aging test;
3. Multi-tube series and parallel aging test: series-parallel constant voltage aging and series-parallel constant current aging;
4. Single-tube constant current aging test.
In both Test 1 and 3, as long as one LED has a quality failure, such as short circuit or open circuit of the LED, it will affect the working current parameters of other LEDs. Test 2 is better than Test 1 and 3. Changes in the characteristics of any one LED will not affect the aging parameters of other LEDs. But in fact, the method of current limiting by resistance is unreliable. The resistance drift of the resistance itself and the change of the voltage characteristics of the LED itself will seriously affect the LED parameters. Obviously, Test 4 captures the LED current working characteristics and is the most scientific LED aging method.
Aging test is a very important process, but it is often overlooked in many enterprises. Correct and effective aging cannot be carried out, and the analysis of parameters such as brightness and wavelength of the LED itself will not be accurate.
Overcurrent impact aging test is also a test method often used by manufacturers. Usually, a constant current source with adjustable frequency, adjustable current and adjustable duty cycle is used for such aging, in order to judge the quality and life expectancy of the LED in a short time.
When applying LEDs, we often encounter this kind of problem: LED products work normally when they are just powered on, but after lighting for a period of time, there will be brightness reduction, flickering, failure, intermittent lighting and other phenomena. This can cause serious damage to the product.
According to our experience and research, the reasons for this phenomenon are roughly as follows:
1. When applying LEDs to products, there are problems in the soldering process. For example, the soldering temperature is too high, the soldering time is too long, and the anti-static work is not done well;
2. Problems in the LED production process lead to poor quality.
In view of the above 2 possible problems, we propose the following preventive measures:
1. Ensure accurate operation during soldering process;
2. Carry out an aging test on the product.
Aging test is an important guarantee for the reliability of electronic products and the last essential step in production. LED aging test is a very important link in product quality control, but it is often overlooked in many cases. The LED aging test is a countermeasure taken according to the failure rate curve of the product, that is, the characteristics of the bathtub curve, so as to improve the reliability of the product. But this method is not necessary, after all, the aging test is at the expense of sacrificing the life of a single LED product.
In order to ensure the service life of the LED membrane switch, JRPanel's purchasing staff will select those LED products that have passed the proper aging test.
JRPanel aims to provide the highest quality products to everyone.