Does anyone have an experience with buying from Beijing Yuji's High CRI led webstore?

http://store.yujiintl.com/collections/high-cri-led-lights/products/vtc-series-a75-bulb-10w

For a 10W bulb, is the 440lm output a bit low(ish) or does it really take that much power from output to get spectrum right?

Not sure about household bulbs, but for a flashlight, 44lm/W is not so bad if it is 90+ CRI. My most efficient cool white low CRI flashlight runs at betwern 90 and 100 lm/W. A stock sk68 clone is under 40 lm/W.

I have to wonder how difficult it would be to do something similar to what they are doing with the led filament bulbs that have popped up recently https://www.youtube.com/watch?v=H_XiunR-cAQ

ahh, ok thanks!

Excellent spectrum!

It's for VTC 5730 led's or for lamp ? What spectrometer you used ?

Anyone use Yuji BC Series High CRI MCPCB LED 24V Modules ?

Evgeniy, you asked where that spectrum comes from.

Go back up the thread to where I posted that spectrum, originally (not the copy you reposted)

Click on the one I posted, and it will show you the page where the image comes from.
It’s their spectrum from their web page, I did not create it.

(when you post an image link using the little “sunset” icon above the text entry box, it lets you first post the link to the image, and then optionally post the link to the source page, that ’s what I did there)

(I do sometimes post spectra I captured using this: https://publiclab.org/wiki/spectral-workbench

Thanks. (Image removed from Yuji site, 404, but found by web.archive.org.)

you use Yuji led modules ?

Odd, I got to that page earlier this morning.

Nope, curious about them but not up for ordering stuff I don’t know much about.
If they had something like the Luxeon PC Rebel Amber with a bit of phosphor added to improve color rendering, that would be interesting.
But “no blue_ is what I’m mostly looking for that’s hard to find.

Interesting tidbit — even blind people who lack rods and cones still respond to the blue range by having their body clock reset, among other responses:

May be, Yuji 1900K led's ?

That spectrum does look good: http://www.yujiintl.com/packages/high-cri-led-test-reports-candle-white-5630
“candle white” would be an apt description of that light.

The 1900K leds are interesting, but not in their webstore unfortunately.

You can wrote to Yuji managers. May be, Yuji has some 1900K .

Let me see- I might have some 1900Ks. I bought a bunch of 6500K and (another) Violet pumped die and can’t remember if it was the 2700K or the 1900K… they only had them in stock for a few weeks.

Sorry, it’s 2700K VTC. I just found the order number in the inbox… under HIGH CRI Web Store, not Yuji.

After long discussion with Yuji manager I received next answers :
If I want buy modules with VTC led, now available only 3200K modules, only constant voltage, or any other - but you must request (and pay) 50 pcs [modules, not led’s] each type (2700,3200, 5000, 5600K, constant voltage or constant current).
Yuji really want sell it ?

The european pendant to Yuji would be Ledon:
ledon-lamp.com/en/led-lamps/led-lamp-a60-7w-e27/

Most lamps have CRI 90.

90CRI is something within the range of most led manufacturers, Yuji is somewhat special in that all their leds are 95CRI+. Osram has a 96CRI led range, but it is generally very uncommon.

I tried to find what leds are inside the Ledon bulbs, but they have managed to hide that from the internet very well…

You can find some pictures of the used chips here:
fastvoice.net/2014/07/28/im-test-die-erste-integrierte-led-leuchte-von-ledon/
fastvoice.net/2013/12/21/im-test-neue-led-spots-von-ledon-von-sehr-klein-bis-sehr-hell/
fastvoice.net/2012/09/19/jetzt-gewinnen-ledon-sunset-dimming-led-lampe-dimmer/
fastvoice.net/2012/08/23/ledon-sunset-dimming-sensibles-erroten/
fastvoice.net/2012/05/15/led-splitter-dimmer-ledon-rotlicht/
futurezone.at/produkte/energiesparlampen-sind-tickende-zeitbomben/24.580.939

I would love to test a set of 95+ CRI bulbs, those have to look great!

thanks for the links, angerdan, i enjoyed reading some of it :slight_smile: . It seems like they produce their own leds/modules, but might source the led-dies elswhere (somewhere the USA is mentioned).