Review: Bedtime Bulb E27 LED (2200K, CRI95)

I’d like to try using your emitter in a flashlight (right now we use amber emitters in our evening flashlights).

Would you sell the emitter on a 16mm or 20mm board for hobbyist use?

Watermanchris: 100% agree. Plus we have a 5-year warranty, so if the product does fail for whatever reason, it’s pretty easy to get a replacement out of us :slight_smile:

hank: It’s actually a filament operating around 70 V, but we unfortunately don’t sell them. We have a pretty tightly integrated supply chain. You may consider breaking open a bulb and using the filaments from there, but consider using cheaper filament bulbs first to test as they are quite delicate :slight_smile:

Greg Yeutter , Can I become your dealer?

Please send a private message here: Bedtime Bulb | Contact

Thanks!

Actually it would be the custom phosphor I’d like to get hold of.
I could dissolve it, I guess, and paint it over a blue or royal blue LED?

If you’ve patented the phosphor, what’s the patent number?

Ah I see. Patent still pending. Right now, it’s going to be difficult to pull out of the supply chain, but we will reconsider for the future.

thank you for letting me know that even with stable power in Finland, the lights have visible flicker

I hope the manufacturer fixes the problem

well… I dont mean to be snarky
however, you dont seem to have understood maukkas comments.

I suggest you re-read maukkas posts, and let us know when you have fixed your driver

clearly the problem with flicker is not limited to USA, nor to “very unstable voltage”

«It isn’t bug, it is feature» (of filament LED bulbs)

Okay, so if I’m reading all this correctly, they’re phosphor-coated filaments?

Filaments have plenty of thermal inertia that only rather drastic fluctuations should be noticeable. The driver must exhibit some pretty serious fluctuations/dropouts to visibly register. Yeah, I’d say definitely work on that.

People used to grex about “pre-flash” when flicking on moonlight/firefly mode on some lights. Having visible stutter on a lightbulb would be a pretty serious glitch.

@jon_slider It’s unclear why you think I don’t understand this discussion. I can confirm that this is a very rare issue with the US bulbs. We’ve sold 10s of thousands with mostly happy customers. Like I said, we only see visible changes in places with power that’s too noisy.

Maukka was literally the first person to test the first batch we ever shipped to Europe. It’s good to know upfront if we have a potential issue with this batch.

We will keep testing to see if it’s an isolated case or a widespread case with the European version. The prototype did not have this issue, so we are doing an investigation to see what changed from test to production.

@Lightbringer They are LED “filaments.” Similar concept to regular discrete LEDs except shaped differently, plus our custom phosphor. The stability of light output is mostly due to the driver circuit as the diodes themselves can fluctuate very rapidly to changes in input.

Europeans (EU countries + UK only): interested in helping me do a test of my bulb? I’ll send you a free Bedtime Bulb if you don’t mind helping me out with a small experiment.

I want to see if the issue that Maukka had is replicable in other regions of Europe. All I would need you to do is to screw in the bulb, observe it for a few minutes, and see if the light is constant or not. You’re free to do whatever you want with the bulb after the test.

If you are interested, please send me a private message with your name and shipping address. Also specify if you prefer the B22 Bayonet base instead of the E27 screw.

E27 Screw version: https://www.amazon.co.uk/dp/B07XWCNCDJ
B22 Bayonet version: https://www.amazon.co.uk/dp/B07XW7NHQT

Thanks,
Greg

Okay, so when you say “filament” it’s more a form-factor (similar to COB LEDs but on a string vs on a board), and not a heated filament as in incandescent bulbs.

I was curious what kind of phosphor would be thermally excited to produce light… that’s what threw me by use of the term “filament”.

So it would in fact be subject to flicker, etc., if the driver passed through voltage variations (hiccoughs) in the mains supply.

Yep, depending on how well the driver handles variations in the mains :slight_smile:

Where could us fun loving folk buy some LED Phosphors in small quantity? Do you know any good sources?

finds a bunch of suppliers and some information about which phosphors have what color output.
E.g.:

. [link on original page]

Hmmm, I can imagine BLF getting into custom mixed phosphor creation.
Here’s the tech note page on blending phosphors: http://www.intematix.com/uploads/application%20notes/PhosphorBlendingAppNote10Jan2013.pdf

Find a source of the “underling blue LED chip” and start mixing up phosphors.

I recall when the original single-phosphor “office white” fluorescents got driven out by “triple phosphor” high color rendering fluorescent tubes.
Triple phosphor lamps had another advantage, as some phosphors have a long decay time so kept puttiing out light when the AC power 60 cycle went through its zero point or the AC power flickered briefly.

Yeah, I’m a dinosaur.

Not aware of any consumer-level retailers. Maybe talk to Yuji. They can do some low-volume LED finished goods and they mix custom phosphors. Perhaps they could sell the phosphors but I can’t guarantee it.

Even a few grams can be pretty pricey though. A little goes a long way!

This is a cool page just to learn about the contribution of various phosphor materials: LED phosphors | YUJILEDS

Yes. It was phosphor on Yuji store 2 years ago. But now I can not find it in their store. It was really expensive. You do not need it, just believe me.

Yea I never found any affordable samples. Darn. I thought it could be fun and educational to sprinkle it over some flashlight LEDs.

Highly awaited product introduction, now highly appreciated (at least by me - as it fits one distinct deficiency of indoor lighting).

Will definitely grab a few pieces if it will be available in Hungary (both E27 and E14), or nearby, if shipping prices will be reasonable.

I am still awaiting for anybody willing to produce 3400-3600K ‘Soft white’ 95< CRI bulb. That would be a pretty good paper reading light for learning.

Also, a 4500-4800K ‘Neutral white’ 95< CRI could be handy to augment daylight indoors.

I know, right? I discovered from mixing bulbs that 3500K is the sweet spot.
You can do this too by using both 3000K and 4000K in the same fixture. The biggest downside is that the fixture looks odd when you look at it. If only one bulb type could achieve 3500K…