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635 white LEDs burnout question

Stigma

New member
Hi,

Just a quick question regarding the "problem" with displays using white leds burning out faster than the other colors:

How exactly do the white LEDs burn out? Do they gradually diminish in intensity from day1, until ~6months (if used 24/7 at 100%) they do no longer glow?

Or do they work at more or less 100% brightness until they burn out and then suddenly don't work anymore?

In any case I will be using some kind of dimming or something to preserve the LEDs when I am not actively reading the display (which would be 99% of the time), but if they do not gradually dim over time, but rather fail after a long time of use, then I will consider running at something like 20% (somewhat visible) while in "inactive". If they gradually dim I will instead go for a solution that shuts the display off completely instead when it is in "inactive" mode.

A followup questions while I have your attention:

What kind of life-time do the indicator-LEDs (the row on the left side on the 635) have in comparison to the white LEDs? If they burn out much slower (I assume they burn out in the same way as the white?), then I guess it would be wise to use these to display the most "critial" information that is needed "at-a-glace" even when in "inactive" mode.

Thanks in advance for the great (and very swift) service here at the cystalfontz forum. I wish all webshops had as great customer service ^_^

-Stigma
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Joe

New member
With all LED's, you have to deal with "Thermal Management". That means that an LED's light output will gradually diminish directly proportional to the junction temperature of the LED. By the time the light output is at 50-75%, the LED's life is considered over. If the application is designed properly, the LED can last 50-100k hours. The indicator LED's should last a LOOONNNGGG time. The Backlight won't last quite as long.:cool:
 

Stigma

New member
I know that _most_ LEDs don't have an issue with lifetime as they work nearly indefinately. However, the white LEDs apparently "only" have a rated lifetime of ca 10.000hrs.

Ok, so they will gradually burn out. Thats good to know. I will plan my "design" accordingly.

-Stigma
 
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