Amazon, Walmart, Ikea targeted in University of California light bulb lawsuits(reuters.com)
reuters.com
Amazon, Walmart, Ikea targeted in University of California light bulb lawsuits
https://www.reuters.com/article/us-retailers-university-of-california-la/amazon-walmart-ikea-targeted-in-university-of-california-light-bulb-lawsuits-idUSKCN1UP24S
14 comments
The only downside to the filament LED bulbs is the flicker. Much like old fluorescent tubes they flicker at twice the supply frequency due to the very small driver circuitry.
That said I just saw a Big Clive video with a much better driver embedded in the bulb, so tech is getting there.
That said I just saw a Big Clive video with a much better driver embedded in the bulb, so tech is getting there.
Not all filament designs have horrendous flicker—we are selling one that we designed with 8% worst case, usually more like 2-3% [0][1]. That's better than incandescent.
Even the normal non-filament LED bulbs can have high levels of flicker. I found one product claiming to be "healthy" that had around 55% flicker.
Most of the bulbs in The Home Depot are going to flicker a lot, especially the filament LEDs.
[0] Bedtime Bulb: Low-blue, low-flicker light bulb https://bedtimebulb.com/
[1] When I say percent flicker, I am referring to the modulation percentage. A good primer is this article: https://www.dial.de/en/blog/article/ieee-1789-a-new-standard...
Even the normal non-filament LED bulbs can have high levels of flicker. I found one product claiming to be "healthy" that had around 55% flicker.
Most of the bulbs in The Home Depot are going to flicker a lot, especially the filament LEDs.
[0] Bedtime Bulb: Low-blue, low-flicker light bulb https://bedtimebulb.com/
[1] When I say percent flicker, I am referring to the modulation percentage. A good primer is this article: https://www.dial.de/en/blog/article/ieee-1789-a-new-standard...
Regarding the Bedtime Bulb, I see the graph of wavelength vs ... the vertical axis isn't labeled, but I assume it's roughly "amount of light at that wavelength": https://static1.squarespace.com/static/59c9469ae5dd5bc276433...
Two things come to mind, looking at it:
1. The total area under each different bulb looks wildly different. I think normal user behavior would be to get enough of the bulbs to light up a room to roughly a certain brightness; therefore, it's the ratio of blue/green light to other light that matters, and a proper comparison would normalize the total brightness of each bulb. (Otherwise, if bulb A was the same as bulb B except half the brightness, the line on the graph would show bulb A producing impressively less blue light than B.) Is there a reason this normalization wasn't done?
2. The levels of green and blue light, while lower than the comparison 2700K LED, are still far higher than zero. Why not make them zero or near-zero? Is this difficult? Is there research showing that "somewhat less blue" is significantly better? My impression is that humans' perception of brightness is mostly logarithmic, which means 0.5x is a lot closer to x than to, say, 0.1x or 0.01x; I don't know if this carries over to the effect on melatonin production, but my prior hypothesis would lean in that direction.
Two things come to mind, looking at it:
1. The total area under each different bulb looks wildly different. I think normal user behavior would be to get enough of the bulbs to light up a room to roughly a certain brightness; therefore, it's the ratio of blue/green light to other light that matters, and a proper comparison would normalize the total brightness of each bulb. (Otherwise, if bulb A was the same as bulb B except half the brightness, the line on the graph would show bulb A producing impressively less blue light than B.) Is there a reason this normalization wasn't done?
2. The levels of green and blue light, while lower than the comparison 2700K LED, are still far higher than zero. Why not make them zero or near-zero? Is this difficult? Is there research showing that "somewhat less blue" is significantly better? My impression is that humans' perception of brightness is mostly logarithmic, which means 0.5x is a lot closer to x than to, say, 0.1x or 0.01x; I don't know if this carries over to the effect on melatonin production, but my prior hypothesis would lean in that direction.
The unlabeled vertical axis makes it difficult to tell how these are perceived, given the very nonuniform spectral sensitivity of the human eye. As a rule of thumb, it takes five times the power for predominantly blue light, and twice the power for red light, to appear perceptually as bright as green light.
My understanding is that it's still up for debate how linear or nonlinear melanopic sensitivity is, which is the main thing we are attempting to show in the plot.
The main purpose of this graph is to compare "melanopic" light, which is light in the blue-green area between about 400 and 580 nm (the gray curve). This is the sleep-disturbing blue light everyone is talking about, which also includes green, as you remarked. The vertical scale is just relative power from 0-1, for the relative amount of light at each wavelength, as you said.
Why not normalize? Because those other sources are twice as bright. We're trying to compare to a light source people would typically buy. Yes, you could use a ~40 watt incandescent at about the same lumen output, but it would still have a higher melanopic effect. The melanopic ratio for incandescent is usually around 0.50-0.54, which ours is 0.39. You'll also notice that we did not include a daylight LED in our comparison, which is something our competitors do, but we think it's just a ridiculous exaggeration of the effect.
In other words, if you pointed a spectrophotometer at the 4 light sources at a consistent distance and did not normalize, that is roughly the plot you would get.
If we take reading as a use case, there are aspects of our design which enable you to use a source that is half as bright and still read just as well. For one, the CRI and R9 (red color rendering) are very high, basically at incandescent levels. This makes the printed page look better. The beam angle is much wider than a normal LED (most LED bulbs mounted upright will shoot all the light at the ceiling, not where it's needed). And most people simply don't need a 60 Watt bulb (650-800 lumens) to read with, even if they don't yet realize it.
Why not eliminate all blue and green? It's certainly possible, and there are bulbs that do that. The problem is that blue/green-free light is very orange/yellow, and in our testing, most people found the light undesirable and impractical. Our theory is that people would go back to their old higher-blue lighting after some time. In other words, people like white light. However, we are working on a mostly melanopic-depleted source with a slightly different use case.
The point is that it comes down to both spectrum and illuminance (brightness). Everyone else in the market is only considering spectrum. There is an explicit tradeoff between color rendering (CRI, R9, Rf, Rg) and the amount of blue/green reduced. If you can balance those two, and then give someone between 100-200 lux, as opposed to 300+ lux for typical reading light, the melanopic input is much lower and the light is more comfortable to use for most people. Our light will give you about 100-200 lux in a shaded or unshaded lamp at a typical reading distance. But it's hard to explain that from a marketing perspective.
Why not normalize? Because those other sources are twice as bright. We're trying to compare to a light source people would typically buy. Yes, you could use a ~40 watt incandescent at about the same lumen output, but it would still have a higher melanopic effect. The melanopic ratio for incandescent is usually around 0.50-0.54, which ours is 0.39. You'll also notice that we did not include a daylight LED in our comparison, which is something our competitors do, but we think it's just a ridiculous exaggeration of the effect.
In other words, if you pointed a spectrophotometer at the 4 light sources at a consistent distance and did not normalize, that is roughly the plot you would get.
If we take reading as a use case, there are aspects of our design which enable you to use a source that is half as bright and still read just as well. For one, the CRI and R9 (red color rendering) are very high, basically at incandescent levels. This makes the printed page look better. The beam angle is much wider than a normal LED (most LED bulbs mounted upright will shoot all the light at the ceiling, not where it's needed). And most people simply don't need a 60 Watt bulb (650-800 lumens) to read with, even if they don't yet realize it.
Why not eliminate all blue and green? It's certainly possible, and there are bulbs that do that. The problem is that blue/green-free light is very orange/yellow, and in our testing, most people found the light undesirable and impractical. Our theory is that people would go back to their old higher-blue lighting after some time. In other words, people like white light. However, we are working on a mostly melanopic-depleted source with a slightly different use case.
The point is that it comes down to both spectrum and illuminance (brightness). Everyone else in the market is only considering spectrum. There is an explicit tradeoff between color rendering (CRI, R9, Rf, Rg) and the amount of blue/green reduced. If you can balance those two, and then give someone between 100-200 lux, as opposed to 300+ lux for typical reading light, the melanopic input is much lower and the light is more comfortable to use for most people. Our light will give you about 100-200 lux in a shaded or unshaded lamp at a typical reading distance. But it's hard to explain that from a marketing perspective.
Great article. What are the design decisions that affect the amount of flicker? Is it solely based on electronically smoothing out the input voltage, or are there other factors? For example, are there phosphors that are better at smoothing the white light even if the blue is modulated?
Adding capacitance to a "linear" driver design is one way to reduce modulation, with some tradeoffs. There are other power supply designs, such as switch-mode and several variations of "constant current" drivers, which could reduce modulation at a higher cost. Adjusting the frequency also plays a role in mitigating perceived flicker.
In higher-end drivers, you'll often see a hybrid approach, such as constant current between 5 and 100% and PWM below 5%. Drivers with deep dimming down to 0.1% are just using 10-bit PWM. This would be difficult to do in a bulb form factor.
I haven't seen any meaningful research into the persistence of various phosphors. It's an interesting thought. My guess is that there could be some effect, but usually we would just try to improve the power electronics.
In higher-end drivers, you'll often see a hybrid approach, such as constant current between 5 and 100% and PWM below 5%. Drivers with deep dimming down to 0.1% are just using 10-bit PWM. This would be difficult to do in a bulb form factor.
I haven't seen any meaningful research into the persistence of various phosphors. It's an interesting thought. My guess is that there could be some effect, but usually we would just try to improve the power electronics.
I heard IKEA uses the phosphor
Their non-dimmable filament bulbs (silver base) tend to be pretty low flicker, but I found the dimmable ones (gold base) have upwards of 30% flicker, even at full output. Without having done a teardown, I suspect the flicker is due to the power electronics.
I buy the 12v LED filament bulbs made for RVs. They have Edison sockets, which means that in the case of table lamps it's easy to cut off the plug and replace it with a 12VDC wall wart. No flicker & very low power consumption.
The lack of a voltage regulator is quite bad; LEDs reduce their internal resistance as they get hotter, causing them to increase thermal output.
That feedback loop, if not controlled for in some way, can easily destroy the lamp.
You also still need a DC converter unless you prefer a 50Hz hum in your LEDs (which sucks).
That feedback loop, if not controlled for in some way, can easily destroy the lamp.
You also still need a DC converter unless you prefer a 50Hz hum in your LEDs (which sucks).
I've had more success with the LED filament style than the bulbs with the high current converter embedded in the base. The filament versions do have a simple bridge-diode-rectifier + cap. So the flicker should be twice the line frequency ~120Hz in US.
see this for teardown... https://www.youtube.com/watch?v=NffhdAz9pc4
I think the high-current, low-LED count bulbs have more thermal issues and problems with dimmers than filament LED bulbs.
Ultimately, however, I think the best approach is to wire up for LED lights using DC lines and a centrally located converter per room/floor. These tend to be used for more expensive lighting, but hopefully they'll gain more traction in the future. Retrofitting a converter to each bulb just seems wrong.
see this for teardown... https://www.youtube.com/watch?v=NffhdAz9pc4
I think the high-current, low-LED count bulbs have more thermal issues and problems with dimmers than filament LED bulbs.
Ultimately, however, I think the best approach is to wire up for LED lights using DC lines and a centrally located converter per room/floor. These tend to be used for more expensive lighting, but hopefully they'll gain more traction in the future. Retrofitting a converter to each bulb just seems wrong.
Filament LEDs at 120Hz have quite a few problems; there is a large number of people who suffer from medical issues if expose long term.
Reducing the flicker or bringing it beyond the 100 kilohertz range is worth it.
If you use a DC converter, you can pick between high and low LED counts, depending on how much you trust the converter and what it can handle (though a 20W DC converter isn't that large to begin with if you start at 24V LED COBs. The current limiter is a single chip with a precision resistor.
I also agree that the best approach is DC wiring. I've been working on realizing that in my own home, 24-48V DC, with solar option, and using the ground wire in the existing cables for communications, so I can tell the LED to dim digitally instead of having to dim the entire power line.
It's not terribly expensive either, a 100W DC converter runs you about 100€, reusing wiring is free and a DC LED controller for up to 20W is less than 10$ to DIY.
Reducing the flicker or bringing it beyond the 100 kilohertz range is worth it.
If you use a DC converter, you can pick between high and low LED counts, depending on how much you trust the converter and what it can handle (though a 20W DC converter isn't that large to begin with if you start at 24V LED COBs. The current limiter is a single chip with a precision resistor.
I also agree that the best approach is DC wiring. I've been working on realizing that in my own home, 24-48V DC, with solar option, and using the ground wire in the existing cables for communications, so I can tell the LED to dim digitally instead of having to dim the entire power line.
It's not terribly expensive either, a 100W DC converter runs you about 100€, reusing wiring is free and a DC LED controller for up to 20W is less than 10$ to DIY.
> Filament LEDs at 120Hz have quite a few problems; there is a large number of people who suffer from medical issues if expose long term.
No one cares.
Epilepsy or migraines? Good luck anywhere in public.
LED floodlights with unnatural spectrum aimed directly at eye height when browsing any store. Despite use of fresnel with associated hideous fringing the edge of illumination is very abrupt with no chance to adjust. Always 2-10x brighter than needed.
Exposed LED strips everywhere with no shade or proper diffuser leading to an overbright spot surrounded by darkness.
Many flickering. Due to LED ramp-up/-down the strobing is instantaneous.
They are all above and all around and to your side. Of course everyone still carries on with distressing over-illumination. But most establishments gleefully ensure there is always at least one of these directly in your vision, not just illuminating the area.
They see interrogation scenes in movies as optimal settings for work, study, play, and relaxation.
Accessibility? Equal opportunity? Hahahahahahhahahahahahahahahahahhaha. Lighting is more and more inaccessible. Good luck even if you manage to convince them to let you be a weirdo in the dark. Everything is aggressively recessed in fixtures.
The lack of caring could be excused as laziness and ignorance, except that everyone laughs at you and makes faces when you bring it up. It doesn't matter if you speak to your immediate manager at work, or customer service at a business, or whether you speak to the appropriate facilities or HR person. It doesn't matter whether you're brief and to the point or whether you lay out the details and provide references. It doesn't matter how polite or demanding you are.
It's not that it was intended to cripple the weak and exclude invalids from society. But they'll happily take it as a bonus.
Speaking of bonuses: they can give you the side-eye as "environmentally unfriendly" if you dare to raise any issue with LED/fluorescent. (Of course the same people usually oppose nuclear power, proving their bad faith.)
No one cares.
Epilepsy or migraines? Good luck anywhere in public.
LED floodlights with unnatural spectrum aimed directly at eye height when browsing any store. Despite use of fresnel with associated hideous fringing the edge of illumination is very abrupt with no chance to adjust. Always 2-10x brighter than needed.
Exposed LED strips everywhere with no shade or proper diffuser leading to an overbright spot surrounded by darkness.
Many flickering. Due to LED ramp-up/-down the strobing is instantaneous.
They are all above and all around and to your side. Of course everyone still carries on with distressing over-illumination. But most establishments gleefully ensure there is always at least one of these directly in your vision, not just illuminating the area.
They see interrogation scenes in movies as optimal settings for work, study, play, and relaxation.
Accessibility? Equal opportunity? Hahahahahahhahahahahahahahahahahhaha. Lighting is more and more inaccessible. Good luck even if you manage to convince them to let you be a weirdo in the dark. Everything is aggressively recessed in fixtures.
The lack of caring could be excused as laziness and ignorance, except that everyone laughs at you and makes faces when you bring it up. It doesn't matter if you speak to your immediate manager at work, or customer service at a business, or whether you speak to the appropriate facilities or HR person. It doesn't matter whether you're brief and to the point or whether you lay out the details and provide references. It doesn't matter how polite or demanding you are.
It's not that it was intended to cripple the weak and exclude invalids from society. But they'll happily take it as a bonus.
Speaking of bonuses: they can give you the side-eye as "environmentally unfriendly" if you dare to raise any issue with LED/fluorescent. (Of course the same people usually oppose nuclear power, proving their bad faith.)
The number of people suffering under flickery LEDs is actually quite large. It's also easily prevented; don't buy cheap filament LEDs, there are plenty of other LED bulbs you can buy. Problem solved. I don't see why you take this argument ad-absurdum.
Fewer components is good, but too few (and certain switch wiring) and your led bulb can't be turned off due to the capacitance of the house wiring
https://youtu.be/1uEmX5XClPY
https://youtu.be/1uEmX5XClPY
There are necessary components in devices.
I doubt you'd argue "fewer compoments is good" when someone omits the seat belts from a car.
LED lights need some components to work properly. One is a AC/DC power supply that converts the AC power to properly smoothed DC. This is the largest and most complicated part of the device. The second is a current regulator that regulates the amount of current going through the LED. Third is a capacitor that smoothes out the flickering of the grid and power supply.
In some cases you can merge the DC power supply with the current regulator. If you have a current regulator, your capacitor can be a lot smaller since you already compensate for flickering below the bandwidth limit of that regulator.
The largest part is the DC converter, the cheaper bulbs and filament ones basically abuse the LEDs as a DC converter via their diode properties. You can still add a current regulator but it's harder to do and reducing flickering becomes very hard without introducing a lot of capacitance at the AC side.
Having a proper DC converter also avoids lighting the bulb on capacitance since you can define drop off voltages and burn some wattage in there that will eat any capacitive voltage.
I doubt you'd argue "fewer compoments is good" when someone omits the seat belts from a car.
LED lights need some components to work properly. One is a AC/DC power supply that converts the AC power to properly smoothed DC. This is the largest and most complicated part of the device. The second is a current regulator that regulates the amount of current going through the LED. Third is a capacitor that smoothes out the flickering of the grid and power supply.
In some cases you can merge the DC power supply with the current regulator. If you have a current regulator, your capacitor can be a lot smaller since you already compensate for flickering below the bandwidth limit of that regulator.
The largest part is the DC converter, the cheaper bulbs and filament ones basically abuse the LEDs as a DC converter via their diode properties. You can still add a current regulator but it's harder to do and reducing flickering becomes very hard without introducing a lot of capacitance at the AC side.
Having a proper DC converter also avoids lighting the bulb on capacitance since you can define drop off voltages and burn some wattage in there that will eat any capacitive voltage.
Practically all LED lamps have current regulators, either a resistor or capacitor, and in practice this works quite well and is reliable; the flicker is due to a lack of a reservoir capacitor, either because the manufacturer was being cheap, or the lamp doesn't physically have enough room for one.
A simple resistor or capacitor is not a current limiter unless the current it delivers when shorted would be below the maximum the LEDs can handle.
A resistor as a current limiter only works reasonably on low wattage LEDs (ie your cheap 0815 plastic LED) and with a stable power supply. 220V grid voltage isn't stable and the LEDs aren't low power anymore.
You need an active limiter that regulates the current that flows through the LEDs (or monitors the voltage across a shunt in series with all LEDs), otherwise you risk collective meltdown.
A resistor as a current limiter only works reasonably on low wattage LEDs (ie your cheap 0815 plastic LED) and with a stable power supply. 220V grid voltage isn't stable and the LEDs aren't low power anymore.
You need an active limiter that regulates the current that flows through the LEDs (or monitors the voltage across a shunt in series with all LEDs), otherwise you risk collective meltdown.
Not sure what you mean. LED’s don’t have internal resistance. Can you ckarify?
The amount of current LED consume varies (due to varying internal resistance) with its temepture assuming voltage is kept same.
Now, if your LED heats up, it's internal resistance goes down, it sucks more current and it heats up even more and this shortens its lifespan or can kill the LED instantly.
A quality driver should handle grid fluctuations, limit the current (by varying the voltage) and LED should have enough cooling (to not disturb its internal resistance much or go above its optimal operating temperature) but often due to space and cost constraints, it doesn't happen.
Some even use bad capacitors (low capacity, dries faster, low voltage rating so blows up when power surge happens) this induces flicker.
Some use crap LEDs array which does not lit evenly, test for it by lowering the voltage if you see LEDs with uneven brightness across the array or grid, you've bad LEDs.
Low quality components, insufficient design, poor QA, inability handle power surge (both grid and local ones) are primary reason for LED flickers and short lifespan
Why they don't fix it? To minimize cost, which helps bottom line and boosts profit. Customer's experience with LED will vary (depending on if they've surge protectors or not or grid fluctuations, these are local to you and others might have different situation), so you won't instantly know from reviews or feedback online - which LED is good for you unless ofc you reverse engineer and figure out how it works even then you might not be able to figure out quality of components and degradation with time.
Marketing/Sales can fix (hide?) lots of bad reviews and profits can be boosted regardless of underlying quality. Many customers won't pay more because they can't differentiate between quality.
And everyone seem to agree that LED as a technology might not last forever, so why bother boosting lifetime/quality of current bulbs when they'll be replaced and an opportunity to make more money will come along?
And when a new better bulb technology will come along, they all will blame their cost cutting induced quality / life issue on LED technology and then they'll move on doing same with the new technology.
Now, if your LED heats up, it's internal resistance goes down, it sucks more current and it heats up even more and this shortens its lifespan or can kill the LED instantly.
A quality driver should handle grid fluctuations, limit the current (by varying the voltage) and LED should have enough cooling (to not disturb its internal resistance much or go above its optimal operating temperature) but often due to space and cost constraints, it doesn't happen.
Some even use bad capacitors (low capacity, dries faster, low voltage rating so blows up when power surge happens) this induces flicker.
Some use crap LEDs array which does not lit evenly, test for it by lowering the voltage if you see LEDs with uneven brightness across the array or grid, you've bad LEDs.
Low quality components, insufficient design, poor QA, inability handle power surge (both grid and local ones) are primary reason for LED flickers and short lifespan
Why they don't fix it? To minimize cost, which helps bottom line and boosts profit. Customer's experience with LED will vary (depending on if they've surge protectors or not or grid fluctuations, these are local to you and others might have different situation), so you won't instantly know from reviews or feedback online - which LED is good for you unless ofc you reverse engineer and figure out how it works even then you might not be able to figure out quality of components and degradation with time.
Marketing/Sales can fix (hide?) lots of bad reviews and profits can be boosted regardless of underlying quality. Many customers won't pay more because they can't differentiate between quality.
And everyone seem to agree that LED as a technology might not last forever, so why bother boosting lifetime/quality of current bulbs when they'll be replaced and an opportunity to make more money will come along?
And when a new better bulb technology will come along, they all will blame their cost cutting induced quality / life issue on LED technology and then they'll move on doing same with the new technology.
LEDs have an internal resistance, they're not superconductors.
When you switch them on, they have a specific value on that resistance. Due to their internals, as they heat up, this resistance goes down, causing current and thermal output to go up.
When you switch them on, they have a specific value on that resistance. Due to their internals, as they heat up, this resistance goes down, causing current and thermal output to go up.
They have something that is sometimes referred to as "dynamic resistance", which is the inverse of the slope of the forward portion of the V-I curve, and yes, it's mostly constant (at constant temperature).
For example, a typical lighting class LED will have a dynamic resistance in the order of 0.2 to 0.3 ohms. However, in as much as this varies a bit with temperature the change is mostly negligible.
I am also not sure about your assertion that this dynamic resistance decreases with temperature. I took a few minutes to review the datasheets of a dozen OSRAM and Seoul Semiconductor 1W class LED's we use. In all cases the slope of the V-I curve increases slightly with temperature, which means the dynamic resistance decreases slightly with an increase in temperature.
Can you explain the effect you are referring to in greater detail? Always interested in learning something new.
Thanks.
For example, a typical lighting class LED will have a dynamic resistance in the order of 0.2 to 0.3 ohms. However, in as much as this varies a bit with temperature the change is mostly negligible.
I am also not sure about your assertion that this dynamic resistance decreases with temperature. I took a few minutes to review the datasheets of a dozen OSRAM and Seoul Semiconductor 1W class LED's we use. In all cases the slope of the V-I curve increases slightly with temperature, which means the dynamic resistance decreases slightly with an increase in temperature.
Can you explain the effect you are referring to in greater detail? Always interested in learning something new.
Thanks.
Dynamic and internal resistance probably mean different things, afaict, but essentially the internal resistance of an LED is a function of it's temperature. An exponential function in fact; the internal resistance of an LED is an exponential function with the temperature as the inverse in the exponent.
Your dynamic slope would also be sufficient to get runaway meltdown.
Essentially, imagine it like this;
The LED has a starting temperature of 20°C and no power applied. When the appropriate voltage is applied, the LED heats up to 40°C. The dynamic resistance has a small slope, so as a result the dynamic and internal resistance both decrease. The current increases, the voltage is the same, the power output of the package goes up.
The LED now heats to 45°C. The process repeats but because the internal resistance is exponentially inverse related to temperature, it speeds up. The LED is now 55°C.
It repeats again and the LED reaches 75°C. Resistance drops again at the higher temperature, the current increases more. 115°C. At the next step the LED will reach 195°C, due to the exponential increase and likely the solder points will liquify. If the LED still works it'll hopefully melt itself from the PCB before it catches fire.
This can happen incredibly fast, you can counteract it by running the LED well below maximum spec but then you're one power surge or heat surge away from meltdown.
Similar to burning wood, the LED's meltdown requires a sufficient amount of extra heat to trigger, otherwise the exponential heat output is too small and is dissipated.
This is why you need a current controller or atleast limiter so that the LED cannot pull more current than it's designed for.
0: https://www.researchgate.net/publication/49586062_Internal_R...
Your dynamic slope would also be sufficient to get runaway meltdown.
Essentially, imagine it like this;
The LED has a starting temperature of 20°C and no power applied. When the appropriate voltage is applied, the LED heats up to 40°C. The dynamic resistance has a small slope, so as a result the dynamic and internal resistance both decrease. The current increases, the voltage is the same, the power output of the package goes up.
The LED now heats to 45°C. The process repeats but because the internal resistance is exponentially inverse related to temperature, it speeds up. The LED is now 55°C.
It repeats again and the LED reaches 75°C. Resistance drops again at the higher temperature, the current increases more. 115°C. At the next step the LED will reach 195°C, due to the exponential increase and likely the solder points will liquify. If the LED still works it'll hopefully melt itself from the PCB before it catches fire.
This can happen incredibly fast, you can counteract it by running the LED well below maximum spec but then you're one power surge or heat surge away from meltdown.
Similar to burning wood, the LED's meltdown requires a sufficient amount of extra heat to trigger, otherwise the exponential heat output is too small and is dissipated.
This is why you need a current controller or atleast limiter so that the LED cannot pull more current than it's designed for.
0: https://www.researchgate.net/publication/49586062_Internal_R...
Thanks, I’ll dig further and talk to the LED applications engineers to see what they have to say. I can’t find anything other than dynamic resistance in the datasheets or manufacturer application notes.
Litigation finance is de rigueur these days. It's unusual that they've affirmatively stated they're funding it, but it's not unusual for there to be a funder and it's becoming more common for details to emerge in discovery about who the funder is and what the details of the funding arrangement are. It's possible that Longford issued a press release because they know or suspect it'll come out in discovery and want to get out ahead of the issue.
https://abovethelaw.com/2019/07/3-thoughts-on-the-future-of-...
https://abovethelaw.com/2019/07/3-thoughts-on-the-future-of-...
Yeah, the bulbs are pretty awesome. My partner was complaining last year about how the LED bulbs are ugly to look at and really wanted an Edison like bulb but with LEDs. A quick google later and I was shocked to find that idea already existed.
All the filament LED bulbs I have single die LEDs and have drivers embedded into the bottom of the bulb. I haven't seen multi-LED arrangements without drivers in a filament LED bulb yet.
What brands would you recommend?
These are the four patents being asserted, fwiw:
7,781,789, Transparent mirrorless light emitting diode: https://patents.google.com/patent/US7781789B2/en
9,240,529, Textured phosphor conversion layer light emitting diode: https://patents.google.com/patent/US9240529B2/en
9,859,464, Lighting emitting diode with light extracted from front and back sides of a lead frame: https://patents.google.com/patent/US9859464B2/en
10,217,916, Transparent light emitting diodes: https://patents.google.com/patent/US10217916B2/en
Patent numbers found in the PDF of one of the complaints (the one against Walmart) linked elsewhere in this discussion: https://news.ycombinator.com/item?id=20571853
7,781,789, Transparent mirrorless light emitting diode: https://patents.google.com/patent/US7781789B2/en
9,240,529, Textured phosphor conversion layer light emitting diode: https://patents.google.com/patent/US9240529B2/en
9,859,464, Lighting emitting diode with light extracted from front and back sides of a lead frame: https://patents.google.com/patent/US9859464B2/en
10,217,916, Transparent light emitting diodes: https://patents.google.com/patent/US10217916B2/en
Patent numbers found in the PDF of one of the complaints (the one against Walmart) linked elsewhere in this discussion: https://news.ycombinator.com/item?id=20571853
Those patents tell an interesting tale, and one not terribly flattering to the University of California. It looks like back in 2006 they invented and patented a variant of the old-fashioned clear domed LED which uses total internal reflection to redirect the light emitted from the rear of the LED out the front, rather than the reflective metal anvil they usually use. This is obviously not a filament LED. The only thing it has in common is that some filament LEDs put the dies on a transparent substrate, though for the purpose of emitting light out the backside of the filament rather than the front. However, they managed to get a set of claims in the '789 patent so broad that it covered all constructions that emit light out the backside of the LED. (The other three patents were filed after filament LEDs became widespread, claiming priority to earlier patents.)
I can't put something more concrete, but I do remember strong prior art case going back a decade.
> 7,781,789
They claim inventing... a lens? A lens with transparent conductors is still a lens
> 9,240,529
A claim of "shaped" optical element being used with a phosphor. Again, borderline cretinical wording
> 9,859,464
Somewhat inventive per se, but wording basically wants to cover all cases of getting light from all sides of an LED, and not a particular implementation.
"We claim a way to get light from all 6 sides of an LED, but we will not say what it is"
> 10,217,916
... basically a claim on inventing a sapphire LED, which they had nothing to do with. Again, a bare claim
Pains to see those guys got Shuji Nakamura on board just to pump troll patents.
> 7,781,789
They claim inventing... a lens? A lens with transparent conductors is still a lens
> 9,240,529
A claim of "shaped" optical element being used with a phosphor. Again, borderline cretinical wording
> 9,859,464
Somewhat inventive per se, but wording basically wants to cover all cases of getting light from all sides of an LED, and not a particular implementation.
"We claim a way to get light from all 6 sides of an LED, but we will not say what it is"
> 10,217,916
... basically a claim on inventing a sapphire LED, which they had nothing to do with. Again, a bare claim
Pains to see those guys got Shuji Nakamura on board just to pump troll patents.
If you're criticizing the title of the patent or the general field of the invention, then you're missing the point. The scope of the patent is determined by the claims at the end. Those claims are drafted narrowly and only claim what is novel and non-obvious over the prior art, because if they were not then the examiner would not allow the patent. If the claims are non-novel or obvious, then the defendants will quickly challenge the validity of the patents and the case will be over.
I know that better than most of the lot here. Your trust into expertise of patent examiners is misplaced.
I see not a single thing specific in their claims describing a design or manufacturing process for that device which would allow me to make it.
For example, use of a "transparent conductor" connecting things is not a design decision, nor an invention just like using wires to connect electricity. No this not an invention.
I see not a single thing specific in their claims describing a design or manufacturing process for that device which would allow me to make it.
For example, use of a "transparent conductor" connecting things is not a design decision, nor an invention just like using wires to connect electricity. No this not an invention.
A patent does not need to teach you or any other actual person how to make and practice the invention. It only needs to teach the hypothetical "person having ordinary skill in the art" how to make or practice the invention. See, e.g., MPEP 2163.02 [0] and MPEP 2164 [1].
[0] https://www.bitlaw.com/source/mpep/2163_02.html [1] https://www.bitlaw.com/source/mpep/2164.html
[0] https://www.bitlaw.com/source/mpep/2163_02.html [1] https://www.bitlaw.com/source/mpep/2164.html
"the litigation is the first-of-its-kind \"direct patent enforcement\" campaign against an entire industry"
Not the first time. Forgent sued a bunch of companies over the use of JPEG [0].
[0] https://en.wikipedia.org/wiki/JPEG
Not the first time. Forgent sued a bunch of companies over the use of JPEG [0].
[0] https://en.wikipedia.org/wiki/JPEG
And they're not really suing the appropriate industry. Retailers are not infringing the patent. This seems troll-ish. When Apple sued Samsung, they sued Samsung. They didn't sue Verizon, AT&T, etc., that were selling the products.
It's a different situation. Samsung is a big company, whereas the lightbulb vendors are fly-by-night resellers/contract manufacturers that don't care about patents. The patent holder goes after the biggest fish because Target is less likely to disappear than JKLM Filament Light Bulb Importing Ltd.
It seems the statute disagrees with me, but it seems wrong to sue the retailer. Sort of like safe-harbor provisions for copyright violations. I don't think it's practical to expect retailers to vet the functionality of an item against active patents and then audit the wholesaler's patent license portfolio for compliance. More practical would be a takedown system where the patent holder could notify the retailer of infringement, and the wholesaler would have the opportunity to respond, again like how things are handled with copyright. (Not that the process there is without flaws)
> Retailers are not infringing the patent
We normally think about manufacturers being the main infringement target, but the statute also refers to anyone who “makes, uses, offers to sell, or sells” (among other things).
We normally think about manufacturers being the main infringement target, but the statute also refers to anyone who “makes, uses, offers to sell, or sells” (among other things).
You can also read the actual press release from UCSB, instead of reuters' regurgitation of it.
https://filamentpatent.ucsb.edu/
https://filamentpatent.ucsb.edu/
Why would a PR release be any more reliable than a news article? At least mainstream news articles try to maintain the appearance of being unbiased :-)
The news story is just the PR release restated. There is no reporting going on. They even repeated the arguably false statement that this is "the first of its kind", leaving off the one part of the statement that might make it true "by a university".
That was the point of my comment, and I included the link so you could look at both.
That was the point of my comment, and I included the link so you could look at both.
Related: Signify (formerly Philips Lighting) recently lost a judgment by the U.S. International Trade Commission on their patent licensing program [0]. Lighting companies that have fought patent infringement claims against Philips/Signify and similar entities have often won but at a high cost [1]. Many others are intimidated into licensing, or they go out of business.
My understanding is that lot of it boils down to the patents being relatively vague or overly broad coupled with overly aggressive enforcement.
[0] (NOTE: PDF) Signify Loses at the U.S. International Trade Commission in Setback to its LED Patent Enforcement Campaign https://edisonreport.com/wp-content/uploads/2019/07/ITCSigni...
[1] Great analysis of the toll Philips' licensing program has on the industry by WAC Lighting, which has fought infringement claims: W.A.C. Issues Strong Response to Philips ITC Complaint https://www.linkedin.com/pulse/wac-issues-strong-response-ph...
My understanding is that lot of it boils down to the patents being relatively vague or overly broad coupled with overly aggressive enforcement.
[0] (NOTE: PDF) Signify Loses at the U.S. International Trade Commission in Setback to its LED Patent Enforcement Campaign https://edisonreport.com/wp-content/uploads/2019/07/ITCSigni...
[1] Great analysis of the toll Philips' licensing program has on the industry by WAC Lighting, which has fought infringement claims: W.A.C. Issues Strong Response to Philips ITC Complaint https://www.linkedin.com/pulse/wac-issues-strong-response-ph...
Found the complaint in PACER if anyone is interested in reading.
https://www.scribd.com/document/420311557/Complaint-19-06570
https://www.scribd.com/document/420311557/Complaint-19-06570
I'd love to see a patent lawyers view of this case. On the face it looks insane to expect retailers to individually weigh patent claims and somehow force suppliers into licensing agreements with third parties.
You don't need a patent lawyer, just read 35 U.S. Code § 271. " . . . whoever without authority makes, uses, offers to sell, or sells any patented invention, within the United States or imports into the United States any patented invention during the term of the the patent therefor, infringes the patents.
Amazon, Walmart, etc. aren't likely the ultimate targets of the suit. The suits are designed to bring in the producers under the indemnity portion of their contract with the retailer. Its a jurisdictional hook and way to effectively multiply the amount of pressure on the actual infringer, by threatening to cut off their access to the retailer (which could be accomplished in the ITC) and leverage possible contractual damages they face from the retailer. The ultimate goal is to pressure Everlight, Eaton, and whoever else is making the light bulbs to pay for a license, and using Amazon and Walmart to force them to do so.
Amazon, Walmart, etc. aren't likely the ultimate targets of the suit. The suits are designed to bring in the producers under the indemnity portion of their contract with the retailer. Its a jurisdictional hook and way to effectively multiply the amount of pressure on the actual infringer, by threatening to cut off their access to the retailer (which could be accomplished in the ITC) and leverage possible contractual damages they face from the retailer. The ultimate goal is to pressure Everlight, Eaton, and whoever else is making the light bulbs to pay for a license, and using Amazon and Walmart to force them to do so.
this really looks like they are truly after these five large retailers because they probably cannot affect the manufacturers of the products. so in effect a retailer simply should be able to discontinue selling the product but from the press release that is not the goal of the suit. They clearly state they want products using the technology sold but they want to put the onus on the retailer.
to be blunt it is because these retailers have the means to pass on this fee and not necessarily just by individual product sales.
to be blunt it is because these retailers have the means to pass on this fee and not necessarily just by individual product sales.
The retailers have their own store brand filament led bulbs, this alone makes them bigger targets as they are electing to manufacture bulbs with their own branding on them.
Walmart, Amazon and Ikea all make their store-brand bulbs so that makes them a bigger target. Not because they are retailers alone.
https://www.walmart.com/ip/Great-Value-LED-Filament-Light-Bu... https://www.ikea.com/us/en/catalog/products/90432392/ https://www.amazon.com/AmazonBasics-Equivalent-Clear-Non-Dim...
It looks like Amazon may have even pulled their stock now.
https://www.walmart.com/ip/Great-Value-LED-Filament-Light-Bu... https://www.ikea.com/us/en/catalog/products/90432392/ https://www.amazon.com/AmazonBasics-Equivalent-Clear-Non-Dim...
It looks like Amazon may have even pulled their stock now.
Hah, from the court paperwork
> For example, the packaging of the Defendant’s infringing Great Value LED Vintage Edison Light Bulb 4w Deco 2pk (Model: CAD4W22G-2P) touts 13 years of life and savings of up to $184 versus a comparable incandescent light bulb—in a product the Defendant sells for $7.72 per 2-pack as reflected in Exhibit B, discussed below. Case 2:19-cv-06570-PSG-RAO Document 1 Filed 07/30/19 Page 5 of 17 Page ID #:5
> For example, the packaging of the Defendant’s infringing Great Value LED Vintage Edison Light Bulb 4w Deco 2pk (Model: CAD4W22G-2P) touts 13 years of life and savings of up to $184 versus a comparable incandescent light bulb—in a product the Defendant sells for $7.72 per 2-pack as reflected in Exhibit B, discussed below. Case 2:19-cv-06570-PSG-RAO Document 1 Filed 07/30/19 Page 5 of 17 Page ID #:5
FWIW, Ikea manufactures their own bulbs.
Unlikely. Resellers don't do their own specialized electronics manufacturing. They likely do like other resellers and have them contract manufactured or slap their brand on some generic parts.
Ikea isn't just a reseller. And they might not own any factories, but neither does Apple.
In many segments, IKEA acts like apple but there are other segments were IKEA is like Amazon Basics. It just depends if they've the patents/know-how which they can leverage, if yes - act like apple, if no - act like Amazon Basics.
In a traditional business, if a retailer imports an item for sale, who else would be responsible for making sure it complied with US law?
As another ooster has said. The law is pretty clear. Anyone selling is responsible.
What matters is the supplier agreement between retailers and suppliers. As another poster has said, that should heavily favor the retailers. Very interesting case because the fly by night operators that are amazon suppliers will be forced out, leaving a few that will de facto have to comply with US IP laws, even though de jure, they would be inmune
What matters is the supplier agreement between retailers and suppliers. As another poster has said, that should heavily favor the retailers. Very interesting case because the fly by night operators that are amazon suppliers will be forced out, leaving a few that will de facto have to comply with US IP laws, even though de jure, they would be inmune
"According to the university’s lawyers at Nixon Peabody, the litigation is the first-of-its-kind 'direct patent enforcement' campaign against an entire industry."
Didn't the CSIRO from Australia do something similar with respect to their wifi patents?
Didn't the CSIRO from Australia do something similar with respect to their wifi patents?
I'm pretty sure UCB isn't producing and selling light bulbs, so as a classic NPE (non practicing entity) they are in the eyes of the law nothing but a patent troll.
Not that that may help much.
Not that that may help much.
Yes but the ability for a university to patent a technology is to fund future research off royalties. NPEs aren't automatically trolls but rather trolls are NPEs.
I have concerns of universities and patents. I am leaning towards 'if you want to hold patents and be a non-profit, then all patents must be free use'. I could be convinced otherwise
> I could be convinced otherwise
Besides the fact that innovation needs to be funded? These things don't happen in a bubble, and financial reward has historically proven to be the greatest driver of innovation.
Besides the fact that innovation needs to be funded? These things don't happen in a bubble, and financial reward has historically proven to be the greatest driver of innovation.
The Bayh-Dole act certainly has screwed things up in the academy though.
I suppose it depends if you want your taxes to increase to keep funding the universities while private companies capitalise on their research for free.
Its happened before. I can't believe its not a worse problem (source, I worked at company before it let everyone go and started litigation. Google settled.)
https://arstechnica.com/information-technology/2008/01/googl...
https://arstechnica.com/information-technology/2008/01/googl...
What’s the difference between a troll and an NPE? I thought they meant the same thing, but that NPE was just the nicer term.
In my head a troll is someone attacking entities for no reason but to further their own pocketbooks, and often using sleazy behavior like attacking entities who cant defend themselves with baseless lawsuit.
An npe who did the initial research, continues to do research, and attacking entities that are able to defend themselves, I would be hard pressed to call a troll unless there is some other sleazy behavior.
An npe who did the initial research, continues to do research, and attacking entities that are able to defend themselves, I would be hard pressed to call a troll unless there is some other sleazy behavior.
The prototypical patent troll didn’t develop the patent, but rather acquired it some time later, and for the purpose of filing lawsuits.
> they are in the eyes of the law nothing but a patent troll.
Patent troll is merely a term used by critics of the patent system for inventors or patent owners whose actions they disagree with. It is not term that is used anywhere in the law itself.
Patent troll is merely a term used by critics of the patent system for inventors or patent owners whose actions they disagree with. It is not term that is used anywhere in the law itself.
>>they are in the eyes of the law nothing but a patent troll.
They invented the technology (according to the claims anyway) so call them whatever you want. You want to use someone's invented tech? Pay for it.
They invented the technology (according to the claims anyway) so call them whatever you want. You want to use someone's invented tech? Pay for it.
What's the patent being infringed? Surely "low-voltage components in series with their combined maximum rating above the mains voltage" by itself can't be patent-worthy, so there should be something more specific being infringed.
https://patents.google.com/patent/US7781789/ "a light emitting diode (LED) that emits light out of the LED from multiple sides of the LED, wherein all layers of the LED are transparent for an emission wavelength except for an emitting layer."
https://patents.google.com/patent/US9240529/ "an LED chip emitting light at a first wavelength, wherein the emitted light is extracted from both front and back sides of the LED chip; a lead frame to which the LED chip is attached, wherein the LED chip resides on or above a transparent plate in the lead frame that allows the emitted light to be extracted out of the LED chip through the transparent plate in the lead frame; and a phosphor for converting the light emitted by the LED chip at the first wavelength to a second wavelength."
https://patents.google.com/patent/US9859464/ "A light emitting device, comprising: a lead frame including a transparent plate; and an LED chip, attached to the lead frame, for emitting light; wherein the LED chip resides on or above the transparent plate and at least some of the light emitted by the LED chip is transmitted through the transparent plate; and wherein at least a portion of the light emitted by the LED chip is extracted from a front side of the lead frame and another portion of the light emitted by the LED chip is extracted from a back side of the lead frame."
https://patents.google.com/patent/US10217916/ "A light emitting device, comprising: a lead frame having a transparent plate therein; and a light emitting diode (LED) chip, mounted on the lead frame and placed on or above the transparent plate in the lead frame, emitting light through at least front and back sides of the LED chip; wherein the transparent plate in the lead frame allows the light emitted from the LED chip to be extracted out of the LED chip from the front or back sides of the LED chip and through the transparent plate in the lead frame."
https://patents.google.com/patent/US9240529/ "an LED chip emitting light at a first wavelength, wherein the emitted light is extracted from both front and back sides of the LED chip; a lead frame to which the LED chip is attached, wherein the LED chip resides on or above a transparent plate in the lead frame that allows the emitted light to be extracted out of the LED chip through the transparent plate in the lead frame; and a phosphor for converting the light emitted by the LED chip at the first wavelength to a second wavelength."
https://patents.google.com/patent/US9859464/ "A light emitting device, comprising: a lead frame including a transparent plate; and an LED chip, attached to the lead frame, for emitting light; wherein the LED chip resides on or above the transparent plate and at least some of the light emitted by the LED chip is transmitted through the transparent plate; and wherein at least a portion of the light emitted by the LED chip is extracted from a front side of the lead frame and another portion of the light emitted by the LED chip is extracted from a back side of the lead frame."
https://patents.google.com/patent/US10217916/ "A light emitting device, comprising: a lead frame having a transparent plate therein; and a light emitting diode (LED) chip, mounted on the lead frame and placed on or above the transparent plate in the lead frame, emitting light through at least front and back sides of the LED chip; wherein the transparent plate in the lead frame allows the light emitted from the LED chip to be extracted out of the LED chip from the front or back sides of the LED chip and through the transparent plate in the lead frame."
This sounds like a garbage patent. People have been stacking LEDs in series since they were invented. They put them on a single, transparent substrate. Big deal, seems obvious to me. Is there something special they developed, like a nifty manufacturing technique or previously unused materials?
How long until Bezos wakes up and starts doing something to curate/monitor third-party retail products even a little? I know most of their customers don't care about patent infringement but this case is just a byproduct of Amazon's unwillingness to address the problem third-party sellers have become.
Right now the killer online is:
"Buy from us, we dont sell cheap knockoffs"
However no one can bring amazon to task, since all the other ones (walmart target etc) are also moving in the same direction...hopelessly trying to catch up with amazon
"Buy from us, we dont sell cheap knockoffs"
However no one can bring amazon to task, since all the other ones (walmart target etc) are also moving in the same direction...hopelessly trying to catch up with amazon
good, somebody should sue these people for making bulbs that give people headaches!!!
I feel like filament LED bulbs were invented in China, or at least that's where I saw them (and LED lighting in general) used far more widely first.
Relatedly, the bigclivedotcom YouTube channel has a huge collection of detailed analysis of various types of LED lighting.
Relatedly, the bigclivedotcom YouTube channel has a huge collection of detailed analysis of various types of LED lighting.
I'm pretty sure filament LED bulbs were invented in China - and patented by their Chinese inventors at the time too. The University of California seem to be suing using broad, trollish patents on things like omitting the rear reflector and allowing LED dies to emit light in all directions. Also, most of the patents were filed after LED filaments became widespread on the market using tricks with patent priority. (The other odd thing is that a lot of LED filaments don't do this - they have a rear reflective metal strip that forms the main structure of the filament.)
> tricks with patent priority.
It's not a trick because in order to assert priority based on a prior application, the invention claimed needs to be completely supported by the prior disclosure. In fact, an applicant will often claim less than what they can in a first application, for a variety of reasons.
It's not a trick because in order to assert priority based on a prior application, the invention claimed needs to be completely supported by the prior disclosure. In fact, an applicant will often claim less than what they can in a first application, for a variety of reasons.
What you feel doesn't matter to what is. Many were developed and made in China, but that doesn't mean they have the IP rights secured to sell in any or all markets where other patent holders registered the idea first.
If they were made in China before the patent was filed, I think that would be prior art, meaning the patent is invalid.
Until the US switched to a “first to file” country like China.
Are you referring to the Leahy–Smith America Invents Act of 2011? It sounds like that still says prior art stops the ability to file.
> Actions and prior art that bar patentability under the Act include public use, sales, publications, and other disclosures available to the public anywhere in the world as of the filing date, other than publications by the inventor within one year of filing (inventor's "publication-conditioned grace period"), whether or not a third party also files a patent application. The law also notably expanded prior art to include foreign offers for sale and public uses.
https://en.wikipedia.org/wiki/Leahy-Smith_America_Invents_Ac...
> Actions and prior art that bar patentability under the Act include public use, sales, publications, and other disclosures available to the public anywhere in the world as of the filing date, other than publications by the inventor within one year of filing (inventor's "publication-conditioned grace period"), whether or not a third party also files a patent application. The law also notably expanded prior art to include foreign offers for sale and public uses.
https://en.wikipedia.org/wiki/Leahy-Smith_America_Invents_Ac...
Public sale or publication still acts as prior art in first to file.
Could be they used the publication grace period: you can be first to publish an invention publicly and then have a one year grace period to file and can use that publication as priority.
Could be they used the publication grace period: you can be first to publish an invention publicly and then have a one year grace period to file and can use that publication as priority.
Separately, if you haven't tried filament LED bulbs, you should. They are a wonderfully simple design: stack lots of small LED's in string so that they can be run at full wall voltage. The lack of a voltage converter means that there are fewer parts to fail, and the long string of LED's makes heat dissipation a lot easier. I find them better than all the alternatives.