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

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…

It’s definitely possible as there are a number of 3500K LEDs, especially those with high CRI and/or “human-centric” SPDs. So it could become a thing. We are listening!

That would be awesome. Just be sure you beat the Hyperikon brand on price or quality:

Date Saved,9/19/2019 2:05:11 PM
Title,HYPERIKON_01_2887K

Measuring Mode,Ambient
Color Space / White Point,HSI,D65
CCT [K],2887
⊿uv,–0.0009
Illuminance [lx],1600
Illuminance [fc],149
Reference CCT [K],5500
LB Index [MK⁻¹],–165
LB Camera Filter,80A, 82B
LB Lighting Filter,R3203 3/4 CTB, R3204 1/2 CTB
CC Index,0.1G
CC#,0.2G
CC Camera Filter,CC025G
CC Lighting Filter,——-
CRI Ra,93.0
CRI R1,95.0
CRI R2,99.6
CRI R3,96.0
CRI R4,92.8
CRI R5,95.0
CRI R6,95.9
CRI R7,89.3
CRI R8,80.2
CRI R9,59.3
CRI R10,98.8
CRI R11,94.9
CRI R12,84.1
CRI R13,96.9
CRI R14,98.7
CRI R15,90.2
TM-30-18 Rf,90
TM-30-18 Rg,96
SSIt,83
SSId,52
SSI1,—-
SSI2,—-
TLCI,91
TLMF,—-
CIE1931 x,0.4438
CIE1931 y,0.4039
Hue,33deg
Saturation,78%



I am eagerly waiting for this to happen :partying_face:

For this, I could imagine 2000 lumens ceiling bulb version as well, and maybe 1300 and 800 lumens for smaller spaces to be illuminated.

Additionally, many of the 95-ish CRI LED light sources still have a mild to moderate gap in the cyan part of the spectrum. If a phosphorus compound set could be tuned to diminish this gap, that would be awesome.

I hope it happens too, I like the bedtime bulb focus on quality. If they made a 3500K bulb with good CRI I would pay good for that.

Unfortunately making bulbs better CRI and brighter at the same time isn’t going to happen with current tech. The more you fiddle with the spectrum, the less efficient the bulb becomes. That makes it run hotter and dimmer.

Hyperikon’s Amazon page is filled with pictures of lights that have melted components or nearly burnt bases, so I would assume “quality” is the direction they would be going for given the price range and niche of this bulb.

Source? I see a 4.2 star product with 2053 reviews and only three people that posted pics of damaged bulbs over all the years on amazon. I’m a happy customer too.
https://www.amazon.com/gp/product/B0779CDXXT/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

Interesting, must be a different product listing or they “cleaned up” their reviews like so many products on Amazon do.

I really wanted to pick some up a few months ago but the first couple pages of reviews I saw were all negative with many pics of discolored/melted bases.

On the other hand maybe they have improved their heat sinks?

The product page looks the same as I recall it 1 year ago when I bought my first Hyperikon. They do sell bulbs in different form factors. Maybe you were looking at a different model. Perhaps with a small form factor and high power?

Thanks to Greg Yeutter (@yeutterg) for sending me a free Bedtime Bulb for testing the output fluctuation issue! I have no advanced measuring equipment with logging capabilities, so I took a video of a white wall and sped it up ten times to make any fluctuations more visible.

This video captures eight minutes of the Bedtime LED Bulb with fixed camera settings, played back at 10x speed. Included is the view at a multimeter measuring the AC mains voltage which varied between 235 V to 237 V. This is for Celle, Germany.

During the test there was no visible fluctuation of the light output and I couldn’t notice it in this sped up video.

Overall the bulb looks good, but I prefer a color temperature of around 3500 K. I’m not a follower of the anti blue light conspiracy, but love high CRI and a variation of color temperature for different moods. If you don’t mind the 2200 K of this light, the spectrum looks really nice (thanks @maukka). The output is too low for productive use, but I think this makes a really great bedside light (as intended!).

The only issue I’ve found is the sensitivity to static electricity. Just pulling off the bubble wrap was enough to light up the LED filaments! Touching and slightly rubbing the clear part of the bulb with the bubble wrap caused the light to flicker, without even touching the metal contacts.

Thanks for the test! I’ll take my bulbs to a couple different locations and check the behavior.

Looks pretty good SammysHP. There is a flicker at 13.5 seconds, but it may just be a video compression issue.