Nichia Optisolis 2700-6500K color and CRI testing

Flashlight Modding and DIY Parts
7

Got some more Nichia Optisolis, this time the whole shebang: 2700-3000-3500-4000-5000-6500 K.

All the measurements can be found here:

Nichia Optisolis 2700-3000-3500-4000-5000-6500K - Album on Imgur

The tint and CRI on these is amazing. The 5000 K is truly a daylight simulator with practically perfect color rendering. You can also see that the peak on the 5000 K and 6500 K emitters is significantly lower at the purple wavelength. The dip above it is also much shallower than the typical cyan dip in a LED spectrum.

Just look at the spectrum!

Here’s a 4000 K with the low peak at a typical higher wavelength and a clear dip above it which reduces the color rendering indices just a bit. But in turn their Rg value is above 100 which means they oversaturate some color a bit, which might be preferable to some.

I also tested the output on the 3000 K and 5000 K variants up to 400 mA. Somewhat surprisingly the 3000 K is more efficient on lower currents but as the current is increased the 5000 K flies past. Forward voltage is higher on the 5000 K one as expected. I found it also amusing that I happened to get a perfect average 3000 K emitter, since its output was bang on 24.1 lumens at 65 mA just like Nichia specifies.

The tint was only tested with bare emitters. There’s barely any tint shift as can be seen from the OP, but Clemence tells me that these don’t work very well in clear optics as a quad at least but a frosted one is fine. It’s could also be quite difficult to find a suitable reflector. My go to Pineapple OP one did exhibit clear shifts in the hotspot. However, a beaded TIR optic looked excellent.

8

Thank you so much Maukka for such invaluable data. Too bad the 5000k doesnt have perfect duv or slightly negative duv. The hint of green kills it for me.

9

I guess I’m not the only one skipping the 2700K, 3500K, 4000K, and 6500K spectrum tests. I waited and kept waiting for the other tests. Until Maukka sent me an email and told me it was there already…. :person_facepalming:
Very nice Maukka. Big thanks. I hope your Carclo 10623 works with the quads.

- Clemence

10

As Clemence posted on his sales thread, the L757 (2700-4000 K) can’t be installed in parallel with the W757 (5000-6500 K) series because the forward voltage difference is too high. Here’s a comparison:

I’m so happy I have automated this. Would have taken ages to put down those numbers manually.

11

Yup, I know how it feels inputting those numbers. I did exactly the same 100mA increments too……manually. Does your Rigol comes with PC UI? Or did you build an add-on DAC hardware? Really like those sweep automation.

- Clemence

12

The Rigol has some software from the manufacturer but it’s utter crap. This Excel file is just using some modified VISA VBA examples from Keysight IIRC which interfaces with the PSU over ethernet. The same thing is much easier to do in Python, which I use when doing the output measurements in the sphere, since it’s simple to integrate the spectrometer executables. Everything just gets written in a CSV file like this:

Voltage;Current;Power;X;Y;Z;Y;x;y;Y;CCT;deltae;CRI;R9;
2,6191;0,0072;0,019;33,509278;31,382019;10,213829;31,382019;0,446165;0,417841;31,4;2959;10,911796;94,9;78,7;
2,6558;0,0173;0,046;70,160871;65,747864;21,881268;65,747864;0,444647;0,416680;65,7;2974;10,125240;95,4;80,6;
2,6829;0,0274;0,073;105,653433;99,082192;33,895346;99,082192;0,442748;0,415211;99,1;2993;9,159034;95,6;81,3;

Where Y is the lux reading from the meter. This has to be converted to lumens of course, but that happens automatically when I paste the data into Excel.

13

Thanks for the info! Now I know testing multiple LEDs is not that hard for you. More incoming Nichias for you then…. :wink:
Slowly but sure, you’ve becoming the top one stop tester for us in WWW.

BTW, do you think it’s possible to spectra testing a male firefly? I’m serious here…

- Clemence

14

I have done everything manually in my led-testing years so I’m glad for you too that you automated it :slight_smile:

My new spectrum-toy (a Mavolux Base) needs a minimum of 10 lux on the (7mm diameter) sensor to produce a spectrum, you may get that if you tape the firefly on top of the sensor :partying_face: . I do not know about maukka’s setup?

15

A hotel manager asked me if I can find a suitable LED to mimic firefly in the hotel garden. He wants it to be as realistic as possible. Weird request but very interesting! Finding/programming a driver with random natural blinking is another challenge.

We can place several fireflies in a small light bulb diffuser in front of the sensor. But I don’t know how Maukka would get those creatures in Finland.

- Clemence

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I found this article from 1964

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Wow Djozz, very informative document you got there! Big thanks. I’ll try to find the suitable LEDs for it. Different species different spectral distributions too. 500nm - 700nm seems to be the range. But the peaks are species dependant. Now I’m thinking to lure fireflies……

- Clemence

18

It looks like a phosfor converted green has about correct width of the emission peak but has the wrong peak wavelength (520nm for the new E21A converted green). The Rebel PC-lime however has its peak at 545nm which comes close to some of the firefly species tested in the 1964 article.

19

PC lime… interesting….
Let’s see if the next E17A green samples I will be receiving looks good. Want some Djozz? :wink:

- Clemence

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Of course I’d love some. Brand new leds, hmmmm :heart_eyes:

A quickndirty spectrum of my flaslight with Rebel PC-lime:

21

This should be enough to satisfy human eyes. Nobody would see the difference. Where did you get that PC Lime Djozz?
I will send some Red Green Blue Amber E17As to you when I get them.

- Clemence

22

Not sure where best get the Rebel lime at the moment, I got them years ago from a portugese aquarium seller that has disappeared since. I see Ledsupply, Luxeonstar and Digikey, so all american sources. There is a Luxeon Z with the same colour as well at Digikey.

Btw, I have quite a stash (30 or so, would have to count them) of 20mm Rebel Sinkpads doing nothing, got them free from vestureofblood a few years ago. I could send them if they are suitable for your project (those Rebel lime leds put out up to 1000 lumen if needed :sunglasses: )

23

I see that RS-online has the Luxeon Z lime (Luxeon Z has a simple two-pad footprint, like the E21A) for more than $5 a piece, a pretty expensive led but I could order there and send them.

24

Thanks for the offer Djozz but let’s wait, until I get those Green E17A first. If they’re good enough then I don’t need the PC lime. Besides E17A form factor is better suited than the bigger lumileds. I think green E17A inside a yellow plastic cap (or yellow heat shrink tube) would look very close to the green-yellow firefly light to the eyes. I just noticed that my Armytek’s green switch LED looks somewhat PC lime behind it’s yellow silicone button.

- Clemence

25

The Luxeon Z is tiny, hardly larger than its 1x1mm die. And what I remember from European fireflies the 530nm greens do not match that colour.
(Lampyrus noctiluca: )

(being persistent here :stuck_out_tongue: )

26

How did you install those Luxeon Z on it? Did you ask it to carry the battery pack too?

Anyway, I just checked one of your test that I never seen before. OMD, this thing is just too small. But yes, the colour spectrum is very close to firefly.

- Clemence