LEDs vulnerable to physical shock?

I have some square four-pin LEDs made by HP which are fairly breakable. The problem is in bending the leads along the wide direction without any support (i.e. using the flimsy epoxy case for support), which tends to crack off a side. Same thing from shock, bouncing LEDs into each other inside the package, could happen.

I bet the clear epoxy is weaker than the black filled epoxy they usually use for ICs. Which certainly makes sense.

I've also thermally stressed at least one: the funny part here is, it's perfectly fine, except the bond wire cracked somewhere. So it doesn't work at 2V (red), but a little pressure on the package and it lights up just fine.

Tim

They can't constrain you from reselling them nor from reverse engineering them, at least in the USA. They can enforce patents and copyrights.

A trade secret isn't one if examination of the product reveals the information.

John

My experience is that these are only as touchy in this area as many to most other LEDs are.

This sounds to me like fairly usual advice for 3 and 5 mm diameter and sililar size epoxy body through-hole-mounting LEDs.

InGaN LEDs at full current usually achieve Class II intensity, especially ones that are especially efficient.

It appears to me that these LEDs have at least close to usual durability. And I expect extreme longevity in the application that I mentioned, since mechanical durability appears to me at least almost-usual and the component values that I mentioned would give this LED less than 1% of its maximum current rating.

Maybe they are. I have often found Nichia to have LEDs a bit favorably different from any others I can find. I have yet to find a non-Nichia low power green LED as efficient or as good at very low currents as this one.

This one appears to me to have overall luminous efficacy maximized at unusually low current around 1.4-1.75 mA, achieving 120-140 lumens/watt at currents in this range. Overall luminous efficacy appears to me to be at least that at 20 mA until current is decreased to less than .2 mA, maybe down to around .1 mA.

Other InGaN low power green and blue LEDs, including older Nichia models, tend to have overall luminous efficacy maximized around 2.2-3.6 mA so far in my experience.

Cree has some green ones available via Digi-Key that I just found to be not too bad a runner-up to Nichia green ones for efficiency at usual and at very low currents. I just tried comparing a Nichia NSPG520AS to a Cree CP41B-GFS-CM0N0784. The latter had only very slightly less output than the former at 20 mA, and more than half as much at .25 mA. Cree 5 mm types may have better low current performance than the 4-pin one I mentioned, but I am not aware of any with wide beam angles that I consider best for indicator lamp usage.

- Don Klipstein ( snipped-for-privacy@misty.com)

Take a look at this:

Note luminous intensity at 20mA is quoted at 20000mcd! It has a 30 degree beam angle which I think is a little smaller than the one you quoted.

Mark.