Any lights using XB-D?

[moozooh]

It's basically a smaller and somewhat brighter version of XP-E2, might just be the best LED for compact throwers. Yet I don't remember a single light advertised as based on this emitter. Why might that be? Am I missing something important here?

 

[Toaster79]

Might be because of the remote phosphor technology and faceted die. Just like XT-E.

 

[moozooh]

Would you elaborate? I see it listed on Cree's site among "consumer portable" applications, such as, quoting, "flashlights, head lamps and lanterns".

 

[Toaster79]

People have experienced color shifting using TIR lenses and reflectors with XT-E, so the story about XB-D might be prety much the same.

 

[A10K]

I briefly used an XB-D and XT-E in some bike lights. While marketed as direct drop-in replacements for the XP-E and XP-G respectively, the remote phosphor technology have them very pronounced color separation and fairly underwhelming throw. The XP-E2 has about the same output and a much cleaner die, so my guess is that it will be a much better candidate for small throwers.

 

[bose301s]

XB-D is not using remote phosphor, remote phosphor would mean using a blue LED the like the XT-E Royal Blue and the applying phosphor to the lens of the device.

 

[Toaster79]

Am I missing something here?

 

[Optical Inferno]

XB-D is not using remote phosphor, remote phosphor would mean using a blue LED the like the XT-E Royal Blue and the applying phosphor to the lens of the device.

It is considered a remote phosphor device as the phosphor is not applied directly to the LED die but to the dome of the LED. This in turn acts the same way as you have described but at the component level. This is what is leading to the colour separation that the others have observed.

 

[Mike S]

It looks as though the phosphor is applied directly to the die... or are you saying that the phosphor is suspended in the silicone dome, and doesn't directly touch the die?

Edit: To clarify, I mean is it suspended by a fraction of a millimeter above the die?

 

[bose301s]

It is considered a remote phosphor device as the phosphor is not applied directly to the LED die but to the dome of the LED. This in turn acts the same way as you have described but at the component level. This is what is leading to the colour separation that the others have observed.

The phosphor IS on the die.

 

[Toaster79]

The phosphor is on the die and all over the base of the LED. It's a layer between the LED base and the silicone dome which covers the entire base.

 

[Optical Inferno]

The phosphor is on the die and all over the base of the LED. It's a layer between the LED base and the silicone dome which covers the entire base.

What he said... therefore it acts as a remote phosphor system and thus gets the designation. The XT-E white also does the same thing I believe.

 

[bose301s]

What he said... therefore it acts as a remote phosphor system and thus gets the designation. The XT-E white also does the same thing I believe.

So then every white LED would be remote phosphor. It's just a different way of applying it but it isn't remote phosphor.

 

[Optical Inferno]

So then every white LED would be remote phosphor. It's just a different way of applying it but it isn't remote phosphor.

If you want to get technical, then your right however... in the case of the XB-D and XT-E White the phosphor is not just limited to the die like other LEDs. This distinction (as can be seen in the image a few posts above) is what causes it to act like a remote phosphor device.

I'm not saying that people should market their device that uses such LEDs as a remote phosphor light, but it will show the colour separation characteristics that are inherent with remote phosphor lights with an optic. This is the likely reason that most people tend to not use them for flashlights and more likely would use them for "opticless" downlights or floodlights.

 

[Gunner12]

Cree's datasheet does not have the word "remote" on it. Just did a quick search and didn't find it. It might be on a picture, but I don't think so.

 

[Optical Inferno]

Cree's datasheet does not have the word "remote" on it. Just did a quick search and didn't find it. It might be on a picture, but I don't think so.

You're absolutely right. They don't mention the term remote phosphor. However, what I and a couple others are suggesting is that it acts like a remote phosphor due to the phosphor not being strictly confined to just the led die.

 

[Gunner12]

That does look like the case from the pictures, unless Cree somehow made dome shaped dies. If it is suspended, the main improvement I can think of is a decrease in phosphor temperature and easier to make. First should be good for increasing phosphor's life a bit (guessing from personal and other experience with overheating LEDs), and second would be good for price.

The amount of light hitting the phosphorus should still be similar to other LEDs due to the proximity to the die, unlike on a remote phosphorous light, where the light density at the phosphor is a good bit lower then with a normal white LED (I've only seen the Philips L-prize bulb).

I think at this close range, the LED is probably most similar to a traditional LED then a remote phosphor device (from the limited experience that I have at least).

 

[Optical Inferno]

I think at this close range, the LED is probably most similar to a traditional LED then a remote phosphor device (from the limited experience that I have at least).

Couldn't agree with you more. I was more referring to the fact that this acts at the emitter level like a remote phosphor device. Yeah... definitely not the same as a remote phosphor light.

 

[bshanahan14rulz]

I think the term you folks are looking for is "conformal coating." Bose is correct in that the raised structure is structurally part of the die and not of the dome, i.e. when they make the die, or if you were to buy a bare die, it would have that clear structure bonded to it.

I think the phosphor around the edges of the die maybe will give a glow that would mess with the beam quality of tight optics.

 

[bose301s]

Look at the Chips portion of our website, you can find the DA1000, DA700 and DA3547 chips. What goes into the XB-D and XT-E are DA chips, the patterned top part is part of the die itself, this die is then coated with phosphor, just like a flat die in the XM-L, XP-G etc. it just looks different because of the conformal coating over the PCB and the non-flat chip.

If you find an old XR-E you will find that the entire surface of what you can be seen below the some is covered with phosphor, that's the same principle as what's happening here and I know no one would ever argue an XR-E is a remote phosphor device. Again, it would be the same as if the covered the entire PCB area under the silicone dome of the XM-L with phosphor instead of just the chip, just a larger applied area but again, not remote phosphor, just like the XB-D and XT-E are not remote phosphor.