Venom
October 17, 2022, 12:18pm
21
Correllux:
I don’t think you can nail one brand or one emitter model for that. Really does depend on several factors. The domes on most emitters don’t put out the same light across every angle of emission so there is always some tint shift at various points. Reflectors and optics help to gather and blend that light so it’s more homogeneous but it doesn’t always happen cleanly of course (type, width and depth, height of the emitter in relation to the base of the reflector, etc). Nichia is usually known for great CRI and tint, but again…you can get cruddy or less-nice bins from them like you can with any other manufacturer. People have been saying a lot that the Sofirn LH351Ds lately have been greenish. None that I’ve gotten from Sofirn have been overly green at all, and the bins that I bought from Simon and Digikey were fantastic (I hear Hank has nice ones, too, but I don’t have any of that emitter in the lights I have from him). But it’s entirely possible that they decided to save a penny and chose a cheaper bin, or perhaps they got what they could get their hands on in the midst of component shortages the last couple years. I think all manufacturers have more or less the same ordering and product structure, but Cree is famous for having some cost saving bin programs (one is the “Easy White” group where the emitters received won’t be as exact as some of the individual listed bins on the datasheets…less specific and that gives them less wasted product or skus that aren’t moving, so they can offer them at a slight savings). So….you can start with wanting, say, a 5000K color temperature, and then you further choose the qualities by the bins that are available. Bins are so important but are like 95% left out of consumer advertising. They specify the chromatic qualities as well as the efficiency (voltage and output). The same 5000K emitter may have five or eight bins listed on a datasheet (but in real life, perhaps only three or four are actually available to buy…).
So…read up on the binning and give the datasheets a good examination…looks all greek at first but it’s fairly straightforward. And ask the manufacturers if they’ll provide that binning information for you (either text or sometimes a photo of the label on the reel)…then you can go for an educated decision and hope they did a good combo with the rest of the business end of the light. Sometimes they’ve shared that in threads here when asked, or one of us chimed in with the details after asking them in private.
What Nitecore told you is probably accurate but even if the emitter is flowed correctly and sitting flat on the board, that’s not a guarantee against the tint shift or rings and such, since that is a major function of the interplay between emitted light and the reflector/optics it’s being pushed into. Sometimes you can change gaskets and improve a beam’s quality, or swapping a reflector from smooth to textured, or to a plastic optic, etc.
In the datasheet you’ll also see a spatial distribution graphic that shows how the brightness and tint shifts present themselves on a bare emitter…most of them look really similar to each other but you’ll see bigger differences between domed and flat emitters for that representation.
So it’s really the whole package of parts plus the skill of both the designers and the assembly workers, not just an LED model.
I guess I’m been lucky with Sofirn light. Been happy with the tint.
When I spoke with the rep at Nitecore. He replied that, He watch the boss take a light with ugly green rings around the hotspot/outer ring. Did some cleaning up from the manufacturing process. Then put everything back together. Now the ugly green rings are gone. Nitecore can’t take apart every light with the ugly green rings.
The Thrunite lights I have, has the greenish tint. It’s nothing major but noticeable.
Does slicing/de-doming the dome off the LED improves the beam tint? I read it’s popular.
Sometimes, can make it worse too. Depends on lots of things really, but largely on the type and tint of LED you start with.
Venom
October 17, 2022, 8:56pm
23
If you start off with ugly tint. Will I still have ugly tint after de-doming?
Is it possible to change the tint this much after de-doming the LED?
Correllux
October 18, 2022, 1:09am
24
Slicing and dedoming are usually done to increase throw, notsomuch for changes in tint or temp but both of those are affected by the lost of the dispersion dome. Generally some intensity is gained while overall lumens will take a loss (in a reflector anyway). There are some great old threads here if you search those terms…beam shots as well as measurements (and techniques for getting the job done nicely…).
Venom
October 18, 2022, 11:14am
25
Thanks for the suggestions everyone!
@Correllux
Thanks for the informational replies, Appreciate it!
