Testing full spectrum Yujileds lightbulbs

SAH

Hi everybody,

Quick reminder about me : I'm a computer scientist, living in France. I have a hard time trying to find usable smartphones/lightbulbs/monitors/TV since LEDs became popular. I still own a 2016 Xperia X compact, and can't find any monitor, I only buy refurbished CCFL screens. About lighting, I can use incandescent and halogen lightbulbs all day long with no problem, and I have no issues with sunlight, but as a child I already had a problem with the typical bright white neons in stores. I can't find any LED lightbulb comfortable : visible wire, frosted glass, 5000K, 4000K, 2700K, in shops, bars, restaurants, at work. Nevertheless, I can use flickering CCFL screens, with and without dithering, and even flickering halogen lightbulbs, I'm a bit lost about the root cause of my problems. I have the feeling (but I have no evidence) that it could be related to light spectrum and color reproduction.

I see a lot of nice reviews about waveform lighting, I wish I could buy such lightbulbs. But the shipping for Europe is absolutely crazy (around 80$).

Today, I decided to give a try to another competitor in the market of "flicker-free" (we're never sure) high-CRI, high R9, full spectrum lightbulbs : yujileds.

https://store.yujiintl.com/

Price is quite high as you can see on my screenshots, but shipping is 25$. Right now there is a big discount because it's their 17th birthday.

I found them on this video comparing different types of bulbs with a precise spectrometer : halogen, CFL, waveform lighting, yujileds, philips.

https://youtu.be/UKOhKmFOjCE

To give it a try, I ordered GU10 6.5W lightbulbs and E27 10W lightbulbs.

I will give you a review when I will get them.

I'm both excited and worried, because I don't have too many options left since the halogen ban. Fingers crossed !

Feel free to tell me if you have tried this brand.

Have a good day

smilem

Lidl stores have nice cheap LED light bulbs that do not flicker and are +95CRI for few Euros. But you need to have equipment to confirm that they do not flicker and that spectrum is OK. They like to sell random crap, most of the time they are OK. The driver is the problem here. They never promise no flicker on the box, but they do state +95CRI.

SAH

smilem Thanks for this valuable information. I have a Lidl close to my house so I'll check it out. I definitely wish a cheaper lightbulb would be usable for me. The main problem of such lightbulbs is that I may not get the complete spreadsheet, and CRI is just a small index (avg of R1-R8) and most lightbulbs have a low R9. But it's definitely worth a try ! I need to find a device to measure extended CRI, flicker, spectrum. I've seen a cheap lightmaster g3 but it lacks some measurements.

Update about my Yuji Leds : it's delivered by DHL, comes from China, and is estimated to arrive on Monday 22nd, which is quite fast. I had to pay 37 extra euros (20% of the price, almost 40$) for French customs (TVA).

Sunspark

Don't forget you can still buy EU voltage bulbs off Alibaba and have it shipped to you.

SAH

Sunspark You're right, I bought a few GU10 on it not too long ago, really cheap and comfortable for me !

I'm on this adventure to look for LED lightbulbs for two reasons, one is curiosity, to find a potential root cause of my problem, and the other is about heat. Now that I'm looking for them for my new appartment, the maximum Watts allowed in new lamps is quite low. I don't know if it's related to a lack of heat dissipation in modern lamps ?

SAH

I received the lightbulbs on Thursday, delivery was really fast. The protection of lightbulbs in the box could have been better, but no lightbulb seems damaged.

The lightbulbs are a bit heavy, they seem really well built.

I tried them for many hours, especially the GU10. The light is really even, clear, pure, and the reflectors don't create any darker spot like my halogen reflectors. Nevertheless, it's supposed to be 2700K but I don't get the same color as with my 2700K halogens bulbs.

The most important : how do I feel. Sadly, I get the same symptoms as for unusable TVs, screens and lights quite quickly. My muscles get tense around my eyes, and they hurt and get really dry. I woke up with dry eyes after using them for the whole evening in my bedroom. If I use them for a long time, I get the typical brain fog and tiredness.

To sum up, it's bad news for me again. I have no idea how I can find usable LED lights now, and the reason why they are unusable.

I ordered tons of halogen bulbs on amazon and some specialzed european websites still selling them. E27, E14, GU10, B22, I bought a lot of them to be comfortable for the next few years at home.

KM

Same here, I am waiting for years for those violet-chip LEDs hat had been announced years ago, but it seems they never made it to the shelves. All we got is White (O)LED, and of course lots of flicker. My symptoms are similar, and I suspect it's a spectrum issue, too. It does not easily explain why we have no problems with sunlight, as the sunlight's spectrum should contain anything sent out by an LED bulb in much higher intensity.

SAH

KM Exactly, especially with such high quality LEDs, that have a really high IRC, close to halogen, incadescent, sun… and a wider and more balanced spectrum than classic LED lightbulbs. Sometimes I wonder if it's related to infrareds or heat produced by black body radiation, or if it's the shape of the wave of flickering (maybe more sinusoidal for halogen, and square for LED), or finally the type of coating used to spread the light.

About the violet-chip LEDs, are you talking about Sunlike chips made by Seoul Semiconductor ?

https://prog.world/new-remez-lamps-with-solar-spectrum/

https://www.digikey.com/catalog/en/partgroup/sunlike-cob-series/87837

If so, there are companies selling them. For Europe, I can see Remez company that allows pre-ordering. They used to have problems with lightbulbs burning out quickly in the past. https://remezlight.com/en/production/office-light/led-bulbsz/.

I can see some for GE and Nord in the US.

Here is the full list : http://www.seoulsemicon.com/en/technology/sunlike/casestudy/