# XP-E vs XR-E



## gcbryan (May 11, 2010)

My computer has problems with Adobe and therefore Cree datasheets.

Can someone give me the quick rundown on the differences between the XR-E and the XP-E.

Specifically how do the die sizes compare. I hear that they are the same and it's just the packaging that is smaller with the XP-E. If so this wouldn't affect throw or hotspot size or spill size.

I know that the XR-E has an emitter beam angel of 90 degrees and the XP-E of 115-120 degrees or somewhere in there.

This would increase in the XP-E either hotspot size or intensity. Which?

I've heard some say that the hotspot is more narrow in the XP-E than the XR-E? If that is the case what is the mechanism for that?

If the die is smaller I get it. If not I don't get it.

Can someone shed some light on this?

Thanks.


----------



## znomit (May 11, 2010)

gcbryan said:


> I know that the XR-E has an emitter beam angel of 90 degrees and the XP-E of 115-120 degrees or somewhere in there.
> 
> This would increase in the XP-E either hotspot size or intensity. Which?



Yeah nah. :thinking:

Yeah: Reflectors grab the light coming out the side of the LEDs and focus it to give the throw. A wider beam angle (XPE) will throw better.

Nah: Aspherics grab the light coming out the front of the LED. A narrow beam agle (XRE) will throw better.

TIR optics are in between.

Yes they both use the same EZ1000 die (some are using the slightly smaller EZ900 die too).


----------



## gcbryan (May 11, 2010)

znomit said:


> Yeah nah. :thinking:
> 
> Yeah: Reflectors grab the light coming out the side of the LEDs and focus it to give the throw. A wider beam angle (XPE) will throw better.
> 
> ...



All things being equal (both in a reflector) the XP-E may have a brighter hotspot than a XR-E but it will be no narrower correct? This is because they both have the same die. This is nothing going on in this comparision that would cause the XP_E to result in a beam coming out of the reflector that was any narrower than a XR-E right?


----------



## bshanahan14rulz (May 11, 2010)

Well, do you have an XP-E and an XR-E side-by-side? Whichever die looks smaller will focus tighter.

I'm thinking the XR-E would throw better, but the XP-E would have more lumens in the hotspot.


----------



## gcbryan (May 11, 2010)

bshanahan14rulz said:


> Well, do you have an XP-E and an XR-E side-by-side? Whichever die looks smaller will focus tighter.
> 
> I'm thinking the XR-E would throw better, but the XP-E would have more lumens in the hotspot.



I don't have them side by side. I'm now told (from another thread) that indeed they both do have the same die but that the XP-E has a dome that makes it look smaller so the apparent die size is smaller and will therefore have a narrower beam.

Just to address what you are saying before having the above info...why do you think the XR-E would throw better if they both have the same die size?

You might reason that the XP-E would have a larger hotspot due to the emitter beam angle (I think that's what you were thinking of with your comment) but what is it about the XR-E that made you think it would throw further. Due to it's beam angle it would have more spill. Were you thinking that maybe it had a smaller die size? Just curious about the logic.

Thanks.


----------



## old4570 (May 11, 2010)

I tried a lot of XP-E R2's when they first come out , and the XR-E just killed them for throw and output ...

I have a XP-E R3 which is supposedly rated to 1A now , but still the XR-E is better ...

I have ATM one XP-E R2 and one XP-E R3 , and where they shine is with lower powered drivers , 500mA to 750mA ..

For all around use , the XR-E R2 is still a good choice .. And the XR-E is maturing , some of the more recent ones have shown increased output from what I was getting 6 or more months ago . I have what is supposed to be a Q5 light that is just blowing away my older R2's . even makes a XP-G R3 look weak .

Now could be a good time to get a hot R2 [ XR-E ] , before everyone swaps over to XP-G , or wait 6 or more months for the next Cree offering [ 160L per 350mA and possibly rated to 1.5A ]


----------



## gcbryan (May 11, 2010)

I have XR-E R2 lights. I'm not looking for a light. This was a theoretical question.

Someone said the XP-E had a narrower beam than the XR-E. I wanted to know if this was true and if so why it was true.

What was different that would make that true. They both use the same die. The die determines the hotspot size. From that point of view the hotspot beam size should be the same.

They have a different emitter beam angles with the XP-E having the wider emitter beam angle so when used with a reflector it should have less spill and more lumens in the hotspot...so brighter and may throw a little further because of that.

However, I later learned that it has a different dome and this makes is appear to have a smaller die and this apparent die size is why it has a narrower hotspot.

I just wanted to make sure all that was true or not true or not accurate or whatever.

I'm asking about the actual physics of what is going on rather than asking about how the emitters function from one flashlight to another.

In two flashlights where everything else is the same is it true that the XP-E would have a narrower beam than a XR-E under those same circumstances?

And I guess I should say justify your answer. Except that sounds rude and that's not my intention. 

So, if you know these emitters well from a technical point of view and you care to settle this question (from another thread) and for my future knowledge I'd appreciate your response.


----------



## old4570 (May 11, 2010)

gcbryan said:


> I have XR-E R2 lights. I'm not looking for a light. This was a theoretical question.
> 
> Someone said the XP-E had a narrower beam than the XR-E. I wanted to know if this was true and if so why it was true.
> 
> ...



its not just the DIE ! , also the LENS has a lot to do with it , and the XP-E - XR-E are like chalk and cheese when it comes to the lenses .


----------



## kaichu dento (May 11, 2010)

old4570 said:


> its not just the DIE ! , also the LENS has a lot to do with it , and the XP-E - XR-E are like chalk and cheese when it comes to the lenses .


You meant the reflector? Cannot be emphasized enough how important matching of the reflector to the chosen emitter is!

Right now while most of the public (CPF public) is enamoured with the xp-g, giving short shrift to the xp-e and almost regarding the xr-e as ancient history, McGizmo xr-e Haiku's are still highly regarded and my Draco's all have beautiful beams thanks to the excellent pairing of their xr-e to the reflector.


----------



## gcbryan (May 11, 2010)

old4570 said:


> its not just the DIE ! , also the LENS has a lot to do with it , and the XP-E - XR-E are like chalk and cheese when it comes to the lenses .



Yes, I understand all of the obvious aspects. I guess no one who has read this post yet has the technical knowledge to respond.

I specified that this is a theoretical question. I specified that everything else being equal. I specified somewhere that we would make the comparison a reflector rather than optic comparision.

I'm not asking about all of the variables in putting together a flashlight system. I know the variables. I know it's not a simple question of which emitter has the narrowest beam in a practical flashlight comparison.

No one so far has answered the question and backed it up with facts.

If it's true that there is an apparent die size difference between the two then it would follow that everything else being kept the same, those two emitters being used in the same reflector either one has more spill and one has more lumens in the hotspot but the hotspot diameter is the same or one has a narrower hotspot diameter in addition to the other aspects because one has a smaller apparent die size.

All other responses have been about everything but what I've directly asked about.


----------



## kaichu dento (May 11, 2010)

gcbryan said:


> Yes, I understand all of the obvious aspects. I guess no one who has read this post yet has the technical knowledge to respond.
> 
> All other responses have been about everything but what I've directly asked about.


Sorry, I only feel comfortable weighing in on things I know a little about and felt inclined to clarify the importance of reflector, not lens.

I'm still watching and hoping to see more of the information you're seeking come up, but a lot of times it really is like going to the park and trying to listen in on the conversation that has the information you're looking for; most of them will be of no relevance to your issue. Sadly, it shouldn't be so when you open a thread like this...


----------



## Ragiska (May 12, 2010)

gcbryan said:


> No one so far has answered the question and backed it up with facts.
> size.
> 
> All other responses have been about everything but what I've directly asked about.



i did exactly that in the other thread, including referencing the VERY basic physics governing your questions. i guess you just didn't like the answer. :shrug:


----------



## gcbryan (May 12, 2010)

Ragiska said:


> i did exactly that in the other thread, including referencing the VERY basic physics governing your questions. i guess you just didn't like the answer. :shrug:


I'm trying to find someone who can speak english and answer in complete paragraphs.


----------



## kaichu dento (May 12, 2010)

gcbryan said:


> I'm trying to find someone who can speak english and answer in complete paragraphs.


If you're concerned with someone speaking better English than Ragiska, then maybe you should watch your capitalization as well. Very rude attitude you've got and I think your thread now deserves to be ignored if you don't adopt a more friendly attitude to the attempt he's made to help you out.


----------



## znomit (May 12, 2010)

kaichu dento said:


> If you're concerned with someone speaking better English than Ragiska, then maybe you should watch your capitalization as well. Very rude attitude you've got and I think your thread now deserves to be ignored if you don't adopt a more friendly attitude to the attempt he's made to help you out.



And he gave an excellent answer. 

https://www.candlepowerforums.com/posts/3380206#post3380206


----------



## gcbryan (May 12, 2010)

kaichu dento said:


> If you're concerned with someone speaking better English than Ragiska, then maybe you should watch your capitalization as well. Very rude attitude you've got and I think your thread now deserves to be ignored if you don't adopt a more friendly attitude to the attempt he's made to help you out.



He's been following me from thread to thread being rude and trying to bait me. Trust me I'm never rude first. Every post is condescending with him. As far as I'm concerned this thread and subject is closed.


----------



## kaichu dento (May 12, 2010)

gcbryan said:


> He's been following me from thread to thread being rude and trying to bait me. Trust me I'm never rude first. Every post is condescending with him. As far as I'm concerned this thread and subject is closed.


Sorry if I spoke too quickly without knowing there was a back-story too. I surely don't envy the mods their duties when it comes to keeping order among our ranks.

Hope you eventually find what you're looking for and that you and Ragiska come to terms as well. For what it's worth I couldn't find anything that seemed deliberately antagonistic in the thread Znomit linked to. Possibly just over-reading or a misunderstanding?


----------



## bshanahan14rulz (May 12, 2010)

The XR-E takes most of its light output and puts it in that 90* output. Think of it as the output of the XP-E, but just closed up from 120* to 90*. Most of the lumens are still there, just in a smaller angle. Coupled with a lens, this would make the XR-E throw much better than the XP-E, as more light is focused by the second lens. You are asking about reflectors, though. I don't have much experience with the XP-E in a reflector.



> If it's true that there is an apparent die size difference between the two then it would follow that everything else being kept the same, those two emitters being used in the same reflector either one has more spill and one has more lumens in the hotspot but the hotspot diameter is the same or one has a narrower hotspot diameter in addition to the other aspects because one has a smaller apparent die size.



I will say, though, to look at the size of the _image_ of the die _at an angle that light would be hitting the reflector from_. I only have XP-G and XR-E right now, but the XR-E's die looks smaller than a picture of an XP-E's die when tilted at the same angle. Far from proof, though, since the XP-E is much smaller overall than the XR-E.

My understanding is this: 
*XR-E works better with a lens, since it already focuses a lot of its light forward for collection into the lens.
*XP-E works better in a reflector, since it has all that side-light that can be utilized by a reflector. This means more light into the hotspot.

Now, where reflectors get messy. The better-focused light will come from the parts of the reflector that are farther away from the LED. The XP-E has a lot more light hitting the reflector, but that advantage that it has over XR-E is taken down a notch by the fact that the wider light is hitting the closer parts of the reflector. This makes for a less collimated beam, but with more total lumens (I won't make any assumptions about lux, though, and lux is the best way to judge throw)
The XR-E in a reflector is utilizing the upper, outer parts of the reflector, since its narrow beam angle keeps it from using the closer, inner parts of the reflector. This results in a tight hotspot. 

Surface brightness also plays a big part in throwyness. Of course, sufrace brightness is affected by the LED lens. Same chip, same brightness, but with a smaller die image will look like it has a higher surface brightness, so you could say that surface brightness affects throwyness the same way that die size does, I guess.

Sorry, but I just felt like dumping my thoughts out here. Not like I'm using them... But hey, maybe someone else can use 'em.


----------



## jeffosborne (May 12, 2010)

Hey bshanahan14rulz, good job! I think you have presented the various elements of the matter very well. Excellent post. Jeff


----------

