How to choose quality LED Source/Chip?

Along with the growing of LED market, there are many LED suppliers, and how to choose the quality LED light source is another problem to the buyers, and you can analyze the following aspects to slove this problem:

1) brightness.
Brightness is one of the most important factor for LED. But the brightness relate with the view angle, different angle, the brightness may have huge difference, take F5 DIP LED as example, when with 180 degree, the brightness is only hundreds MCD, but when use 15 degree, the brightness can achieve 10,000+ MCD, so when compare the brightness, please make sure it’s under the same view angle.

2) anti-static capability.
Usually the LED with better antistatic ability will have longer lifespan, and therefore higher prices. Generally LED for illumination anti-static voltage should be higher than 700V.

3) the wavelength.
If the LEDs with similar wavelength they will emit unanimous color. The suppliers are diffcult to produce the unanimous color LED if they didn’t classify the LED by the wavelength. 

4) leak current.
LED is one-way conductive light, if there is reverse current is called leakage, large leakage current will short LED lifespan.

5) light emitting angles.
Different occasion may use different LED angle. Usually, large area should use the large angle, so that the LED can illuminate more area, and small area or some accent illumination should use small angle, so that the LED can focus more on the necessary area. Consult more from your lighting designer before buying LED sources.

6) lifespan.
The lifespan is the key for the LED quality, and the lifespan depend on the light decay, for low light decay will result long life, on the contrary, high light decay will shorter the lifespan. In theory, the lifespan can be 10,000+ hours when light decay down to 50% of it’s initial value. Take other factors in count, usually the lifespan can be up to 50,000+ or 80,000+ hours.

7) LED Chip.
The chip is for emitting, different chips the quality will be different. The Japanese chip (Nicha) and US (CREE) produce the top quality chips, and there are also many taiwan and South Korea companies that can produce secondary chips, of course with reasonable price.

8) the chip size.
The size is measured by the side of the chip, and the unit is mil, 1mil =1/1000 inch = 0.00254cm = 0.0254mm. Usually, for the LED display, the size need up to 8-11 mil, if for backlight, usually use the 20 x 38 mil or 10 x 23 mil. Of course, the size depend on the LED application.

9) Packing Glue.
Usually, the LED package is epoxy resin. When choosing glue, you’d better select the glue with good liquidity, and the cured glue with good flexibility, can bear high or low temperature, also the glue will be better if mix with anti-UV and anti-file material, so that the LED can meet the outdoor use.

And there are some other aspects that you need to consider when buy LED, such as the safty, the LEDs with GS, UL, CE certificate will be better. And when you need to consider about the environment, take the RoHS or other environment certificates in count.