New LED type that emits "white" light
- Thread starter hirby
- Start date
Help Support Candle Power Flashlight Forum
brightnorm
Flashaholic
- Joined
- Oct 13, 2001
- Messages
- 7,160
Re: New LED type that emits \"white\" light
Very interesting and promising
Brightnorm
Very interesting and promising
Brightnorm
The_LED_Museum
*Retired*
Re: New LED type that emits
Promising, perhaps. But commercial 400nm LEDs only last a few hundred hours to half intensity, a bit more perhaps if underdriven, and a bit less when overdriven. So 400nm LEDs would have to get useable halflives up to 100,000 hours like most other LEDs before these new white "bulbs" would become cost-effective enough to compete with regular bulbs.
Promising, perhaps. But commercial 400nm LEDs only last a few hundred hours to half intensity, a bit more perhaps if underdriven, and a bit less when overdriven. So 400nm LEDs would have to get useable halflives up to 100,000 hours like most other LEDs before these new white "bulbs" would become cost-effective enough to compete with regular bulbs.
James S
Flashlight Enthusiast
Re: New LED type that emits
Craig, but isn't one of the main reasons that the UV led's die an early death the degradation of the epoxy from the UV so they yellow and become opaque to the UV? Or do the dies themselves crap out. If it's just the envelope then by converting the UV into something else before it hits the case it should remove that problem shouldn't it?
Craig, but isn't one of the main reasons that the UV led's die an early death the degradation of the epoxy from the UV so they yellow and become opaque to the UV? Or do the dies themselves crap out. If it's just the envelope then by converting the UV into something else before it hits the case it should remove that problem shouldn't it?
The_LED_Museum
*Retired*
Re: New LED type that emits
I think the dice themselves poop out. There is bound to be some degradation (yellowing) of the epoxy encapsulant, but I believe this to be very minor when compared to the dice themselves going to pot.
Nichia UV LEDs come in metal cans with a glass window or lens, and they poop out pretty quickly (when compared to visible light LEDs) too.
Converting the UV into visible before it reaches the encapsulant would help a little, but ONLY A LITTLE. The UV light emitted by the LED has a high enough energy level in the photons to cause an atomic dissociation in the GaN lattice, causing the LED to slowly eat itself and grow dimmer much more quickly than a visible light LED would.
I think the dice themselves poop out. There is bound to be some degradation (yellowing) of the epoxy encapsulant, but I believe this to be very minor when compared to the dice themselves going to pot.
Nichia UV LEDs come in metal cans with a glass window or lens, and they poop out pretty quickly (when compared to visible light LEDs) too.
Converting the UV into visible before it reaches the encapsulant would help a little, but ONLY A LITTLE. The UV light emitted by the LED has a high enough energy level in the photons to cause an atomic dissociation in the GaN lattice, causing the LED to slowly eat itself and grow dimmer much more quickly than a visible light LED would.
IsaacHayes
Flashlight Enthusiast
Re: New LED type that emits
crazy-ness. UV is some nasty stuff.
crazy-ness. UV is some nasty stuff.
Floating Spots
Enlightened
Re: New LED type that emits
Well, more than one beat me to it.
Interesting read though.
You always gotta start somewhere.
Well, more than one beat me to it.
Interesting read though.
You always gotta start somewhere.
