Flicker Free LED Lightning it's the most important thing! Which one to buy?

I would love to hear from others as well! I’m in the United States and I’m looking, but can’t find any major lighting manufacturer that is currently making flicker-free LED bulbs. Philips and Sunco claim that their bulbs are "flicker-free" in their marketing, but when you take a closer look at the notes (Philips) or talk to a sales rep (Sunco), they acknowledge that they’re only talking about visible flicker. Their bulbs are not free of invisible 120Hz flicker. I’ve been learning more about bulb wiring lately, and it turns out that the manufacturer needs to choose to put an extra circuit into the bulb (a DC-DC converter) to eliminate the 120 Hz flicker created by the AC mains. The cost of adding this is low (about 10 euro cents, according to a report by the Swedish Energy Agency). However, including the circuitry to make a bulb have zero flicker reduces its energy efficiency somewhat - these bulbs have somewhat low power factors. A power factor less than 1 means that some of the energy drawn into the bulb circuitry is lost as heat instead of being used directly to produce light. To qualify for the US Energy Star certification and to be sold in California, bulbs need to have a power factor >= 0.7. My favorite Philips A19 dimmable LED bulbs from 2013 that are completely flicker-free only have a power factor of 0.65 according to LEDbenchmark. The only flicker-free bulbs I’ve been able to find on sale in the US today are A19 bulbs from Waveform Lighting, but their power factor is 0.6 so they can’t be sold in California. [EDIT: as of June 2021, the Waveform bulbs have been updated so their power factor is >0.7 and they can now be shipped to California (Title 20 compliant); I just bought more to put in a family member’s home]. I’m pretty sure that all of their non-filament (normal bulb-style) A19s are flicker-free even if the website labeling is missing. They actually publish the flicker percent and flicker index too! As of a week ago, I own their 2700K Centric Home A19 and 2 of their art-specific bulbs (D50 and D65 A19s). All of these bulbs are actually flicker-free. They have no flicker on a slow-motion video and they’re not causing pain or migraine. Their reviews are from a lot of grateful migraine patients. During a flicker migraine, I find flicker-free LEDs to be even better for me than some incandescents. Waveform also sells drivers for strip lighting/industrial lighting that they advertise as "flicker-free" and that have PWM at 30KHz. I haven’t tried them yet, but am looking at them to maybe use in the classroom.

The lighting industry seems to be abandoning the 2015 IEEE 1789 report recommendations for flicker which were a guess about appropriate limits for invisible flicker based on old studies of the biological effects of fluorescent lights - these standards aren’t strong enough to prevent my migraines from LED flicker. Now the lighting industry is adopting less stringent "SVM" standards and a "Pst" standard that only applies to visible flicker.

Bulbs I’ve tested recently that are NOT flicker-free according to both slow-motion phone video (all have 120 Hz flicker) and according to my flicker-sensitive migraine brain:
Philips "eye-comfort" "flicker-free" PAR20 (model 9290013169).
Philips "eye-comfort" "warm glow" 60W-equivalent 8.8W A19 (model 9290019409B).
Sunco PAR20 bulbs with "flicker-free technology" (model L9-PAR20DWP-7W).
GE 60W-equivalent dimmable 10W A19 (model 67615).
Target Up&Up (store brand) 60W-equivalent non-dimmable 10W A19 (model A800830).

I’m beginning to think that the major US manufacturers may have abandoned making flicker-free bulbs due to the lower power factor and due to the absence of evidence in the medical literature for the biological effects of LED flicker.

I’m curious about a few things:

1. If you live in a country with 50 Hz AC power (so 100Hz flicker from AC), do the LED bulbs sold in your country today flicker at 100 Hz if you take a slow-motion video of them with your phone camera? I’m curious because 100 Hz is around the limit of being visible flicker for some people, so I’m wondering if it’s just the US that’s getting by with making all flickering bulbs since our 120 Hz flicker shouldn’t be visible.

2. Has anyone in the US found any other flicker-free bulbs on the market today that you’ve actually tested in some way? So far, I only know of Waveform, but their product line isn’t comprehensive.

3. Does anyone know of any flicker-free drivers for industrial-style LEDs being sold in the US?

4. I seem to have more migraine trouble from flickering industrial-style LED strip lighting than from the average flickering household bulb even though the strip lighting flickers much faster. Does anyone else have a similar (or different) experience?

5. Other than calling companies or leaving bad reviews, has anyone found any effective action to take against bulb flicker? I’ve tried a few different mostly ineffective things - so far filing a report about bulbs causing the "injury" of migraine with the US Consumer Product Safety Commission has resulted in the best company response - it has resulted in an internal investigation that has included their engineers. I’m not sure whether they’re really doing anything other than verifying the bulb is within their specs for visible flicker, but if companies start to hear about problems through this avenue, it could also create a paper trail for further advocacy. I’m also trying to push the medical community to study this so there will be evidence for policy-makers, but that’s another story.

By the way, if you’re curious, this is how I use my iPhone camera to estimate flicker rate: In the settings, it tells me that the Slo-Mo video rate is 240 frames per second. If your phone has options, set it to the highest frames per second. In the absence of other ambient light, focus on the bulb so the shutter speed is fast - that makes it easier to detect subtle flicker, but it actually doesn’t matter if the flicker is bad. Record the slo-mo video for a few seconds. Upon play-back, you will see obvious flashing from 120Hz flicker. Faster flicker will result in bands of bright/dark moving from one side of the screen to the other. This happens because when taking a single frame of the video, the phone records the image starting on one long edge of the frame and moving toward the other long edge. This means that 120Hz flicker on a 240fps video, when viewed frame-by-frame, looks darker on one side of the frame and brighter on the other side of the frame. The dark and bright regions are on the opposite sides in the next frame. Each frame represents one half of the full cycle so (0.5 cycles/frame) x (240 frames/second) = 120 cycles/second = 120 Hz. With faster flicker, there can be multiple bright/dark phases per frame. On the iPhone, the bands will always be parallel to the long edge of the phone because of the side-to-side way that the phone takes individual image frames in the video. When there are many bands, just count how many dark bands you see per frame since that will tell you the number of cycles per frame. Then multiply as before. For example, if there are 12 dark bands in one frame, (12 cycles/frame) x (240 frames/second) = 2880 cycles/second = 2880 Hz. Obviously, this is just a rough estimate, but it’s not too bad. It’s easiest to see this kind of banding in the part of the image where the lamp is. So if you suspect rapid flicker, getting your phone closer to the lamp so that the lamp fills most of the frame (at least spanning the short direction across the phone) can be helpful to give you a larger area in which to detect banding. Banding can be subtle or obvious, depending on how much the light dims in the dark phase. Flicker-free LED bulbs will not have any flashing or banding in the slow motion video. The light should look so steady that you'll double-check to see if you’re actually playing the video.

I get migraines from industrial LED strip lights with very subtle banding in the video in a pattern suggesting about 1500 Hz flicker. I also get migraines from every household LED bulb with 120 Hz flicker that I’ve ever encountered. I’ve never had a problem with household LEDs that have a 0.00 flicker index. I’ve never had a problem with LEDs that use constant DC power.

Just adding onto this excellent thread. I'd fallen for Philips' marketing and bought their "flicker free" bulbs to relieve my headaches. Since I'm still having headaches, I did some digging and found two documents, which might be the ones @jen found as well.

1. Philips bulbs are manufactured by a company called Signify as referenced here
2. Signify has a document (here) that, if I'm reading it correctly, attempts to discredit the IEEE1789 flicker standard

That second document was enough to confirm for me that Philips/Signify bulbs aren't really flicker-free at all. (Why try to get around a published standard if you're compliant?)

Per this thread, I bought a 6-pack of Waveform bulbs last weekend. Excited for them to arrive. Will report back on how they work out.

I have not found "flicker free" bulbs to b any better or worse than any other bulbs

I purchases pretty expensive certified "flicker free" Cree LED bulbs off Amazon. Triggered symptoms within seconds. I then went to Lowes and bought a box of the 18 count bulk el-cheaper GE LED bulbs. Practically zero symptoms.

Never go by advertising, or hunches, or slogans, or "I think it's this", just go by symptoms. Keep switching bulbs until you find one that works and when you do stock up.

In winter months, incandescent bulbs do not negatively impact my power bill very much, as my heater doesn't have to work as hard with the bulbs helping by providing their own heat- it balances out the higher wattage of the bulbs. At some point, I'd like to do a test, but I wager some LEDs might actually lend to a slightly higher power bill than good old burning wire, in my case.
In summer months, I may consider GE's High CRI HD LEDs- they were pretty decent when I used them. I don't know if they flicker, my sensitive eyes didn't have much issue with them, which is saying a lot as even the difference between the average fluorescent strip and average LED strip is very noticeable for me (I loathe the LEDs at my job).
Regardless, there's just nothing like the pure, even lighting of incandescent.